diff options
Diffstat (limited to 'kernel/tools/net')
-rw-r--r-- | kernel/tools/net/Makefile | 34 | ||||
-rw-r--r-- | kernel/tools/net/bpf_asm.c | 52 | ||||
-rw-r--r-- | kernel/tools/net/bpf_dbg.c | 1395 | ||||
-rw-r--r-- | kernel/tools/net/bpf_exp.l | 146 | ||||
-rw-r--r-- | kernel/tools/net/bpf_exp.y | 780 | ||||
-rw-r--r-- | kernel/tools/net/bpf_jit_disasm.c | 199 |
6 files changed, 2606 insertions, 0 deletions
diff --git a/kernel/tools/net/Makefile b/kernel/tools/net/Makefile new file mode 100644 index 000000000..ee577ea03 --- /dev/null +++ b/kernel/tools/net/Makefile @@ -0,0 +1,34 @@ +prefix = /usr + +CC = gcc +LEX = flex +YACC = bison + +%.yacc.c: %.y + $(YACC) -o $@ -d $< + +%.lex.c: %.l + $(LEX) -o $@ $< + +all : bpf_jit_disasm bpf_dbg bpf_asm + +bpf_jit_disasm : CFLAGS = -Wall -O2 -DPACKAGE='bpf_jit_disasm' +bpf_jit_disasm : LDLIBS = -lopcodes -lbfd -ldl +bpf_jit_disasm : bpf_jit_disasm.o + +bpf_dbg : CFLAGS = -Wall -O2 +bpf_dbg : LDLIBS = -lreadline +bpf_dbg : bpf_dbg.o + +bpf_asm : CFLAGS = -Wall -O2 -I. +bpf_asm : LDLIBS = +bpf_asm : bpf_asm.o bpf_exp.yacc.o bpf_exp.lex.o +bpf_exp.lex.o : bpf_exp.yacc.c + +clean : + rm -rf *.o bpf_jit_disasm bpf_dbg bpf_asm bpf_exp.yacc.* bpf_exp.lex.* + +install : + install bpf_jit_disasm $(prefix)/bin/bpf_jit_disasm + install bpf_dbg $(prefix)/bin/bpf_dbg + install bpf_asm $(prefix)/bin/bpf_asm diff --git a/kernel/tools/net/bpf_asm.c b/kernel/tools/net/bpf_asm.c new file mode 100644 index 000000000..c15aef097 --- /dev/null +++ b/kernel/tools/net/bpf_asm.c @@ -0,0 +1,52 @@ +/* + * Minimal BPF assembler + * + * Instead of libpcap high-level filter expressions, it can be quite + * useful to define filters in low-level BPF assembler (that is kept + * close to Steven McCanne and Van Jacobson's original BPF paper). + * In particular for BPF JIT implementors, JIT security auditors, or + * just for defining BPF expressions that contain extensions which are + * not supported by compilers. + * + * How to get into it: + * + * 1) read Documentation/networking/filter.txt + * 2) Run `bpf_asm [-c] <filter-prog file>` to translate into binary + * blob that is loadable with xt_bpf, cls_bpf et al. Note: -c will + * pretty print a C-like construct. + * + * Copyright 2013 Daniel Borkmann <borkmann@redhat.com> + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +#include <stdbool.h> +#include <stdio.h> +#include <string.h> + +extern void bpf_asm_compile(FILE *fp, bool cstyle); + +int main(int argc, char **argv) +{ + FILE *fp = stdin; + bool cstyle = false; + int i; + + for (i = 1; i < argc; i++) { + if (!strncmp("-c", argv[i], 2)) { + cstyle = true; + continue; + } + + fp = fopen(argv[i], "r"); + if (!fp) { + fp = stdin; + continue; + } + + break; + } + + bpf_asm_compile(fp, cstyle); + + return 0; +} diff --git a/kernel/tools/net/bpf_dbg.c b/kernel/tools/net/bpf_dbg.c new file mode 100644 index 000000000..9a287bec6 --- /dev/null +++ b/kernel/tools/net/bpf_dbg.c @@ -0,0 +1,1395 @@ +/* + * Minimal BPF debugger + * + * Minimal BPF debugger that mimics the kernel's engine (w/o extensions) + * and allows for single stepping through selected packets from a pcap + * with a provided user filter in order to facilitate verification of a + * BPF program. Besides others, this is useful to verify BPF programs + * before attaching to a live system, and can be used in socket filters, + * cls_bpf, xt_bpf, team driver and e.g. PTP code; in particular when a + * single more complex BPF program is being used. Reasons for a more + * complex BPF program are likely primarily to optimize execution time + * for making a verdict when multiple simple BPF programs are combined + * into one in order to prevent parsing same headers multiple times. + * + * More on how to debug BPF opcodes see Documentation/networking/filter.txt + * which is the main document on BPF. Mini howto for getting started: + * + * 1) `./bpf_dbg` to enter the shell (shell cmds denoted with '>'): + * 2) > load bpf 6,40 0 0 12,21 0 3 20... (output from `bpf_asm` or + * `tcpdump -iem1 -ddd port 22 | tr '\n' ','` to load as filter) + * 3) > load pcap foo.pcap + * 4) > run <n>/disassemble/dump/quit (self-explanatory) + * 5) > breakpoint 2 (sets bp at loaded BPF insns 2, do `run` then; + * multiple bps can be set, of course, a call to `breakpoint` + * w/o args shows currently loaded bps, `breakpoint reset` for + * resetting all breakpoints) + * 6) > select 3 (`run` etc will start from the 3rd packet in the pcap) + * 7) > step [-<n>, +<n>] (performs single stepping through the BPF) + * + * Copyright 2013 Daniel Borkmann <borkmann@redhat.com> + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <ctype.h> +#include <stdbool.h> +#include <stdarg.h> +#include <setjmp.h> +#include <linux/filter.h> +#include <linux/if_packet.h> +#include <readline/readline.h> +#include <readline/history.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <sys/stat.h> +#include <sys/mman.h> +#include <fcntl.h> +#include <errno.h> +#include <signal.h> +#include <arpa/inet.h> +#include <net/ethernet.h> + +#define TCPDUMP_MAGIC 0xa1b2c3d4 + +#define BPF_LDX_B (BPF_LDX | BPF_B) +#define BPF_LDX_W (BPF_LDX | BPF_W) +#define BPF_JMP_JA (BPF_JMP | BPF_JA) +#define BPF_JMP_JEQ (BPF_JMP | BPF_JEQ) +#define BPF_JMP_JGT (BPF_JMP | BPF_JGT) +#define BPF_JMP_JGE (BPF_JMP | BPF_JGE) +#define BPF_JMP_JSET (BPF_JMP | BPF_JSET) +#define BPF_ALU_ADD (BPF_ALU | BPF_ADD) +#define BPF_ALU_SUB (BPF_ALU | BPF_SUB) +#define BPF_ALU_MUL (BPF_ALU | BPF_MUL) +#define BPF_ALU_DIV (BPF_ALU | BPF_DIV) +#define BPF_ALU_MOD (BPF_ALU | BPF_MOD) +#define BPF_ALU_NEG (BPF_ALU | BPF_NEG) +#define BPF_ALU_AND (BPF_ALU | BPF_AND) +#define BPF_ALU_OR (BPF_ALU | BPF_OR) +#define BPF_ALU_XOR (BPF_ALU | BPF_XOR) +#define BPF_ALU_LSH (BPF_ALU | BPF_LSH) +#define BPF_ALU_RSH (BPF_ALU | BPF_RSH) +#define BPF_MISC_TAX (BPF_MISC | BPF_TAX) +#define BPF_MISC_TXA (BPF_MISC | BPF_TXA) +#define BPF_LD_B (BPF_LD | BPF_B) +#define BPF_LD_H (BPF_LD | BPF_H) +#define BPF_LD_W (BPF_LD | BPF_W) + +#ifndef array_size +# define array_size(x) (sizeof(x) / sizeof((x)[0])) +#endif + +#ifndef __check_format_printf +# define __check_format_printf(pos_fmtstr, pos_fmtargs) \ + __attribute__ ((format (printf, (pos_fmtstr), (pos_fmtargs)))) +#endif + +enum { + CMD_OK, + CMD_ERR, + CMD_EX, +}; + +struct shell_cmd { + const char *name; + int (*func)(char *args); +}; + +struct pcap_filehdr { + uint32_t magic; + uint16_t version_major; + uint16_t version_minor; + int32_t thiszone; + uint32_t sigfigs; + uint32_t snaplen; + uint32_t linktype; +}; + +struct pcap_timeval { + int32_t tv_sec; + int32_t tv_usec; +}; + +struct pcap_pkthdr { + struct pcap_timeval ts; + uint32_t caplen; + uint32_t len; +}; + +struct bpf_regs { + uint32_t A; + uint32_t X; + uint32_t M[BPF_MEMWORDS]; + uint32_t R; + bool Rs; + uint16_t Pc; +}; + +static struct sock_filter bpf_image[BPF_MAXINSNS + 1]; +static unsigned int bpf_prog_len = 0; + +static int bpf_breakpoints[64]; +static struct bpf_regs bpf_regs[BPF_MAXINSNS + 1]; +static struct bpf_regs bpf_curr; +static unsigned int bpf_regs_len = 0; + +static int pcap_fd = -1; +static unsigned int pcap_packet = 0; +static size_t pcap_map_size = 0; +static char *pcap_ptr_va_start, *pcap_ptr_va_curr; + +static const char * const op_table[] = { + [BPF_ST] = "st", + [BPF_STX] = "stx", + [BPF_LD_B] = "ldb", + [BPF_LD_H] = "ldh", + [BPF_LD_W] = "ld", + [BPF_LDX] = "ldx", + [BPF_LDX_B] = "ldxb", + [BPF_JMP_JA] = "ja", + [BPF_JMP_JEQ] = "jeq", + [BPF_JMP_JGT] = "jgt", + [BPF_JMP_JGE] = "jge", + [BPF_JMP_JSET] = "jset", + [BPF_ALU_ADD] = "add", + [BPF_ALU_SUB] = "sub", + [BPF_ALU_MUL] = "mul", + [BPF_ALU_DIV] = "div", + [BPF_ALU_MOD] = "mod", + [BPF_ALU_NEG] = "neg", + [BPF_ALU_AND] = "and", + [BPF_ALU_OR] = "or", + [BPF_ALU_XOR] = "xor", + [BPF_ALU_LSH] = "lsh", + [BPF_ALU_RSH] = "rsh", + [BPF_MISC_TAX] = "tax", + [BPF_MISC_TXA] = "txa", + [BPF_RET] = "ret", +}; + +static __check_format_printf(1, 2) int rl_printf(const char *fmt, ...) +{ + int ret; + va_list vl; + + va_start(vl, fmt); + ret = vfprintf(rl_outstream, fmt, vl); + va_end(vl); + + return ret; +} + +static int matches(const char *cmd, const char *pattern) +{ + int len = strlen(cmd); + + if (len > strlen(pattern)) + return -1; + + return memcmp(pattern, cmd, len); +} + +static void hex_dump(const uint8_t *buf, size_t len) +{ + int i; + + rl_printf("%3u: ", 0); + for (i = 0; i < len; i++) { + if (i && !(i % 16)) + rl_printf("\n%3u: ", i); + rl_printf("%02x ", buf[i]); + } + rl_printf("\n"); +} + +static bool bpf_prog_loaded(void) +{ + if (bpf_prog_len == 0) + rl_printf("no bpf program loaded!\n"); + + return bpf_prog_len > 0; +} + +static void bpf_disasm(const struct sock_filter f, unsigned int i) +{ + const char *op, *fmt; + int val = f.k; + char buf[256]; + + switch (f.code) { + case BPF_RET | BPF_K: + op = op_table[BPF_RET]; + fmt = "#%#x"; + break; + case BPF_RET | BPF_A: + op = op_table[BPF_RET]; + fmt = "a"; + break; + case BPF_RET | BPF_X: + op = op_table[BPF_RET]; + fmt = "x"; + break; + case BPF_MISC_TAX: + op = op_table[BPF_MISC_TAX]; + fmt = ""; + break; + case BPF_MISC_TXA: + op = op_table[BPF_MISC_TXA]; + fmt = ""; + break; + case BPF_ST: + op = op_table[BPF_ST]; + fmt = "M[%d]"; + break; + case BPF_STX: + op = op_table[BPF_STX]; + fmt = "M[%d]"; + break; + case BPF_LD_W | BPF_ABS: + op = op_table[BPF_LD_W]; + fmt = "[%d]"; + break; + case BPF_LD_H | BPF_ABS: + op = op_table[BPF_LD_H]; + fmt = "[%d]"; + break; + case BPF_LD_B | BPF_ABS: + op = op_table[BPF_LD_B]; + fmt = "[%d]"; + break; + case BPF_LD_W | BPF_LEN: + op = op_table[BPF_LD_W]; + fmt = "#len"; + break; + case BPF_LD_W | BPF_IND: + op = op_table[BPF_LD_W]; + fmt = "[x+%d]"; + break; + case BPF_LD_H | BPF_IND: + op = op_table[BPF_LD_H]; + fmt = "[x+%d]"; + break; + case BPF_LD_B | BPF_IND: + op = op_table[BPF_LD_B]; + fmt = "[x+%d]"; + break; + case BPF_LD | BPF_IMM: + op = op_table[BPF_LD_W]; + fmt = "#%#x"; + break; + case BPF_LDX | BPF_IMM: + op = op_table[BPF_LDX]; + fmt = "#%#x"; + break; + case BPF_LDX_B | BPF_MSH: + op = op_table[BPF_LDX_B]; + fmt = "4*([%d]&0xf)"; + break; + case BPF_LD | BPF_MEM: + op = op_table[BPF_LD_W]; + fmt = "M[%d]"; + break; + case BPF_LDX | BPF_MEM: + op = op_table[BPF_LDX]; + fmt = "M[%d]"; + break; + case BPF_JMP_JA: + op = op_table[BPF_JMP_JA]; + fmt = "%d"; + val = i + 1 + f.k; + break; + case BPF_JMP_JGT | BPF_X: + op = op_table[BPF_JMP_JGT]; + fmt = "x"; + break; + case BPF_JMP_JGT | BPF_K: + op = op_table[BPF_JMP_JGT]; + fmt = "#%#x"; + break; + case BPF_JMP_JGE | BPF_X: + op = op_table[BPF_JMP_JGE]; + fmt = "x"; + break; + case BPF_JMP_JGE | BPF_K: + op = op_table[BPF_JMP_JGE]; + fmt = "#%#x"; + break; + case BPF_JMP_JEQ | BPF_X: + op = op_table[BPF_JMP_JEQ]; + fmt = "x"; + break; + case BPF_JMP_JEQ | BPF_K: + op = op_table[BPF_JMP_JEQ]; + fmt = "#%#x"; + break; + case BPF_JMP_JSET | BPF_X: + op = op_table[BPF_JMP_JSET]; + fmt = "x"; + break; + case BPF_JMP_JSET | BPF_K: + op = op_table[BPF_JMP_JSET]; + fmt = "#%#x"; + break; + case BPF_ALU_NEG: + op = op_table[BPF_ALU_NEG]; + fmt = ""; + break; + case BPF_ALU_LSH | BPF_X: + op = op_table[BPF_ALU_LSH]; + fmt = "x"; + break; + case BPF_ALU_LSH | BPF_K: + op = op_table[BPF_ALU_LSH]; + fmt = "#%d"; + break; + case BPF_ALU_RSH | BPF_X: + op = op_table[BPF_ALU_RSH]; + fmt = "x"; + break; + case BPF_ALU_RSH | BPF_K: + op = op_table[BPF_ALU_RSH]; + fmt = "#%d"; + break; + case BPF_ALU_ADD | BPF_X: + op = op_table[BPF_ALU_ADD]; + fmt = "x"; + break; + case BPF_ALU_ADD | BPF_K: + op = op_table[BPF_ALU_ADD]; + fmt = "#%d"; + break; + case BPF_ALU_SUB | BPF_X: + op = op_table[BPF_ALU_SUB]; + fmt = "x"; + break; + case BPF_ALU_SUB | BPF_K: + op = op_table[BPF_ALU_SUB]; + fmt = "#%d"; + break; + case BPF_ALU_MUL | BPF_X: + op = op_table[BPF_ALU_MUL]; + fmt = "x"; + break; + case BPF_ALU_MUL | BPF_K: + op = op_table[BPF_ALU_MUL]; + fmt = "#%d"; + break; + case BPF_ALU_DIV | BPF_X: + op = op_table[BPF_ALU_DIV]; + fmt = "x"; + break; + case BPF_ALU_DIV | BPF_K: + op = op_table[BPF_ALU_DIV]; + fmt = "#%d"; + break; + case BPF_ALU_MOD | BPF_X: + op = op_table[BPF_ALU_MOD]; + fmt = "x"; + break; + case BPF_ALU_MOD | BPF_K: + op = op_table[BPF_ALU_MOD]; + fmt = "#%d"; + break; + case BPF_ALU_AND | BPF_X: + op = op_table[BPF_ALU_AND]; + fmt = "x"; + break; + case BPF_ALU_AND | BPF_K: + op = op_table[BPF_ALU_AND]; + fmt = "#%#x"; + break; + case BPF_ALU_OR | BPF_X: + op = op_table[BPF_ALU_OR]; + fmt = "x"; + break; + case BPF_ALU_OR | BPF_K: + op = op_table[BPF_ALU_OR]; + fmt = "#%#x"; + break; + case BPF_ALU_XOR | BPF_X: + op = op_table[BPF_ALU_XOR]; + fmt = "x"; + break; + case BPF_ALU_XOR | BPF_K: + op = op_table[BPF_ALU_XOR]; + fmt = "#%#x"; + break; + default: + op = "nosup"; + fmt = "%#x"; + val = f.code; + break; + } + + memset(buf, 0, sizeof(buf)); + snprintf(buf, sizeof(buf), fmt, val); + buf[sizeof(buf) - 1] = 0; + + if ((BPF_CLASS(f.code) == BPF_JMP && BPF_OP(f.code) != BPF_JA)) + rl_printf("l%d:\t%s %s, l%d, l%d\n", i, op, buf, + i + 1 + f.jt, i + 1 + f.jf); + else + rl_printf("l%d:\t%s %s\n", i, op, buf); +} + +static void bpf_dump_curr(struct bpf_regs *r, struct sock_filter *f) +{ + int i, m = 0; + + rl_printf("pc: [%u]\n", r->Pc); + rl_printf("code: [%u] jt[%u] jf[%u] k[%u]\n", + f->code, f->jt, f->jf, f->k); + rl_printf("curr: "); + bpf_disasm(*f, r->Pc); + + if (f->jt || f->jf) { + rl_printf("jt: "); + bpf_disasm(*(f + f->jt + 1), r->Pc + f->jt + 1); + rl_printf("jf: "); + bpf_disasm(*(f + f->jf + 1), r->Pc + f->jf + 1); + } + + rl_printf("A: [%#08x][%u]\n", r->A, r->A); + rl_printf("X: [%#08x][%u]\n", r->X, r->X); + if (r->Rs) + rl_printf("ret: [%#08x][%u]!\n", r->R, r->R); + + for (i = 0; i < BPF_MEMWORDS; i++) { + if (r->M[i]) { + m++; + rl_printf("M[%d]: [%#08x][%u]\n", i, r->M[i], r->M[i]); + } + } + if (m == 0) + rl_printf("M[0,%d]: [%#08x][%u]\n", BPF_MEMWORDS - 1, 0, 0); +} + +static void bpf_dump_pkt(uint8_t *pkt, uint32_t pkt_caplen, uint32_t pkt_len) +{ + if (pkt_caplen != pkt_len) + rl_printf("cap: %u, len: %u\n", pkt_caplen, pkt_len); + else + rl_printf("len: %u\n", pkt_len); + + hex_dump(pkt, pkt_caplen); +} + +static void bpf_disasm_all(const struct sock_filter *f, unsigned int len) +{ + unsigned int i; + + for (i = 0; i < len; i++) + bpf_disasm(f[i], i); +} + +static void bpf_dump_all(const struct sock_filter *f, unsigned int len) +{ + unsigned int i; + + rl_printf("/* { op, jt, jf, k }, */\n"); + for (i = 0; i < len; i++) + rl_printf("{ %#04x, %2u, %2u, %#010x },\n", + f[i].code, f[i].jt, f[i].jf, f[i].k); +} + +static bool bpf_runnable(struct sock_filter *f, unsigned int len) +{ + int sock, ret, i; + struct sock_fprog bpf = { + .filter = f, + .len = len, + }; + + sock = socket(AF_INET, SOCK_DGRAM, 0); + if (sock < 0) { + rl_printf("cannot open socket!\n"); + return false; + } + ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf)); + close(sock); + if (ret < 0) { + rl_printf("program not allowed to run by kernel!\n"); + return false; + } + for (i = 0; i < len; i++) { + if (BPF_CLASS(f[i].code) == BPF_LD && + f[i].k > SKF_AD_OFF) { + rl_printf("extensions currently not supported!\n"); + return false; + } + } + + return true; +} + +static void bpf_reset_breakpoints(void) +{ + int i; + + for (i = 0; i < array_size(bpf_breakpoints); i++) + bpf_breakpoints[i] = -1; +} + +static void bpf_set_breakpoints(unsigned int where) +{ + int i; + bool set = false; + + for (i = 0; i < array_size(bpf_breakpoints); i++) { + if (bpf_breakpoints[i] == (int) where) { + rl_printf("breakpoint already set!\n"); + set = true; + break; + } + + if (bpf_breakpoints[i] == -1 && set == false) { + bpf_breakpoints[i] = where; + set = true; + } + } + + if (!set) + rl_printf("too many breakpoints set, reset first!\n"); +} + +static void bpf_dump_breakpoints(void) +{ + int i; + + rl_printf("breakpoints: "); + + for (i = 0; i < array_size(bpf_breakpoints); i++) { + if (bpf_breakpoints[i] < 0) + continue; + rl_printf("%d ", bpf_breakpoints[i]); + } + + rl_printf("\n"); +} + +static void bpf_reset(void) +{ + bpf_regs_len = 0; + + memset(bpf_regs, 0, sizeof(bpf_regs)); + memset(&bpf_curr, 0, sizeof(bpf_curr)); +} + +static void bpf_safe_regs(void) +{ + memcpy(&bpf_regs[bpf_regs_len++], &bpf_curr, sizeof(bpf_curr)); +} + +static bool bpf_restore_regs(int off) +{ + unsigned int index = bpf_regs_len - 1 + off; + + if (index == 0) { + bpf_reset(); + return true; + } else if (index < bpf_regs_len) { + memcpy(&bpf_curr, &bpf_regs[index], sizeof(bpf_curr)); + bpf_regs_len = index; + return true; + } else { + rl_printf("reached bottom of register history stack!\n"); + return false; + } +} + +static uint32_t extract_u32(uint8_t *pkt, uint32_t off) +{ + uint32_t r; + + memcpy(&r, &pkt[off], sizeof(r)); + + return ntohl(r); +} + +static uint16_t extract_u16(uint8_t *pkt, uint32_t off) +{ + uint16_t r; + + memcpy(&r, &pkt[off], sizeof(r)); + + return ntohs(r); +} + +static uint8_t extract_u8(uint8_t *pkt, uint32_t off) +{ + return pkt[off]; +} + +static void set_return(struct bpf_regs *r) +{ + r->R = 0; + r->Rs = true; +} + +static void bpf_single_step(struct bpf_regs *r, struct sock_filter *f, + uint8_t *pkt, uint32_t pkt_caplen, + uint32_t pkt_len) +{ + uint32_t K = f->k; + int d; + + switch (f->code) { + case BPF_RET | BPF_K: + r->R = K; + r->Rs = true; + break; + case BPF_RET | BPF_A: + r->R = r->A; + r->Rs = true; + break; + case BPF_RET | BPF_X: + r->R = r->X; + r->Rs = true; + break; + case BPF_MISC_TAX: + r->X = r->A; + break; + case BPF_MISC_TXA: + r->A = r->X; + break; + case BPF_ST: + r->M[K] = r->A; + break; + case BPF_STX: + r->M[K] = r->X; + break; + case BPF_LD_W | BPF_ABS: + d = pkt_caplen - K; + if (d >= sizeof(uint32_t)) + r->A = extract_u32(pkt, K); + else + set_return(r); + break; + case BPF_LD_H | BPF_ABS: + d = pkt_caplen - K; + if (d >= sizeof(uint16_t)) + r->A = extract_u16(pkt, K); + else + set_return(r); + break; + case BPF_LD_B | BPF_ABS: + d = pkt_caplen - K; + if (d >= sizeof(uint8_t)) + r->A = extract_u8(pkt, K); + else + set_return(r); + break; + case BPF_LD_W | BPF_IND: + d = pkt_caplen - (r->X + K); + if (d >= sizeof(uint32_t)) + r->A = extract_u32(pkt, r->X + K); + break; + case BPF_LD_H | BPF_IND: + d = pkt_caplen - (r->X + K); + if (d >= sizeof(uint16_t)) + r->A = extract_u16(pkt, r->X + K); + else + set_return(r); + break; + case BPF_LD_B | BPF_IND: + d = pkt_caplen - (r->X + K); + if (d >= sizeof(uint8_t)) + r->A = extract_u8(pkt, r->X + K); + else + set_return(r); + break; + case BPF_LDX_B | BPF_MSH: + d = pkt_caplen - K; + if (d >= sizeof(uint8_t)) { + r->X = extract_u8(pkt, K); + r->X = (r->X & 0xf) << 2; + } else + set_return(r); + break; + case BPF_LD_W | BPF_LEN: + r->A = pkt_len; + break; + case BPF_LDX_W | BPF_LEN: + r->A = pkt_len; + break; + case BPF_LD | BPF_IMM: + r->A = K; + break; + case BPF_LDX | BPF_IMM: + r->X = K; + break; + case BPF_LD | BPF_MEM: + r->A = r->M[K]; + break; + case BPF_LDX | BPF_MEM: + r->X = r->M[K]; + break; + case BPF_JMP_JA: + r->Pc += K; + break; + case BPF_JMP_JGT | BPF_X: + r->Pc += r->A > r->X ? f->jt : f->jf; + break; + case BPF_JMP_JGT | BPF_K: + r->Pc += r->A > K ? f->jt : f->jf; + break; + case BPF_JMP_JGE | BPF_X: + r->Pc += r->A >= r->X ? f->jt : f->jf; + break; + case BPF_JMP_JGE | BPF_K: + r->Pc += r->A >= K ? f->jt : f->jf; + break; + case BPF_JMP_JEQ | BPF_X: + r->Pc += r->A == r->X ? f->jt : f->jf; + break; + case BPF_JMP_JEQ | BPF_K: + r->Pc += r->A == K ? f->jt : f->jf; + break; + case BPF_JMP_JSET | BPF_X: + r->Pc += r->A & r->X ? f->jt : f->jf; + break; + case BPF_JMP_JSET | BPF_K: + r->Pc += r->A & K ? f->jt : f->jf; + break; + case BPF_ALU_NEG: + r->A = -r->A; + break; + case BPF_ALU_LSH | BPF_X: + r->A <<= r->X; + break; + case BPF_ALU_LSH | BPF_K: + r->A <<= K; + break; + case BPF_ALU_RSH | BPF_X: + r->A >>= r->X; + break; + case BPF_ALU_RSH | BPF_K: + r->A >>= K; + break; + case BPF_ALU_ADD | BPF_X: + r->A += r->X; + break; + case BPF_ALU_ADD | BPF_K: + r->A += K; + break; + case BPF_ALU_SUB | BPF_X: + r->A -= r->X; + break; + case BPF_ALU_SUB | BPF_K: + r->A -= K; + break; + case BPF_ALU_MUL | BPF_X: + r->A *= r->X; + break; + case BPF_ALU_MUL | BPF_K: + r->A *= K; + break; + case BPF_ALU_DIV | BPF_X: + case BPF_ALU_MOD | BPF_X: + if (r->X == 0) { + set_return(r); + break; + } + goto do_div; + case BPF_ALU_DIV | BPF_K: + case BPF_ALU_MOD | BPF_K: + if (K == 0) { + set_return(r); + break; + } +do_div: + switch (f->code) { + case BPF_ALU_DIV | BPF_X: + r->A /= r->X; + break; + case BPF_ALU_DIV | BPF_K: + r->A /= K; + break; + case BPF_ALU_MOD | BPF_X: + r->A %= r->X; + break; + case BPF_ALU_MOD | BPF_K: + r->A %= K; + break; + } + break; + case BPF_ALU_AND | BPF_X: + r->A &= r->X; + break; + case BPF_ALU_AND | BPF_K: + r->A &= K; + break; + case BPF_ALU_OR | BPF_X: + r->A |= r->X; + break; + case BPF_ALU_OR | BPF_K: + r->A |= K; + break; + case BPF_ALU_XOR | BPF_X: + r->A ^= r->X; + break; + case BPF_ALU_XOR | BPF_K: + r->A ^= K; + break; + } +} + +static bool bpf_pc_has_breakpoint(uint16_t pc) +{ + int i; + + for (i = 0; i < array_size(bpf_breakpoints); i++) { + if (bpf_breakpoints[i] < 0) + continue; + if (bpf_breakpoints[i] == pc) + return true; + } + + return false; +} + +static bool bpf_handle_breakpoint(struct bpf_regs *r, struct sock_filter *f, + uint8_t *pkt, uint32_t pkt_caplen, + uint32_t pkt_len) +{ + rl_printf("-- register dump --\n"); + bpf_dump_curr(r, &f[r->Pc]); + rl_printf("-- packet dump --\n"); + bpf_dump_pkt(pkt, pkt_caplen, pkt_len); + rl_printf("(breakpoint)\n"); + return true; +} + +static int bpf_run_all(struct sock_filter *f, uint16_t bpf_len, uint8_t *pkt, + uint32_t pkt_caplen, uint32_t pkt_len) +{ + bool stop = false; + + while (bpf_curr.Rs == false && stop == false) { + bpf_safe_regs(); + + if (bpf_pc_has_breakpoint(bpf_curr.Pc)) + stop = bpf_handle_breakpoint(&bpf_curr, f, pkt, + pkt_caplen, pkt_len); + + bpf_single_step(&bpf_curr, &f[bpf_curr.Pc], pkt, pkt_caplen, + pkt_len); + bpf_curr.Pc++; + } + + return stop ? -1 : bpf_curr.R; +} + +static int bpf_run_stepping(struct sock_filter *f, uint16_t bpf_len, + uint8_t *pkt, uint32_t pkt_caplen, + uint32_t pkt_len, int next) +{ + bool stop = false; + int i = 1; + + while (bpf_curr.Rs == false && stop == false) { + bpf_safe_regs(); + + if (i++ == next) + stop = bpf_handle_breakpoint(&bpf_curr, f, pkt, + pkt_caplen, pkt_len); + + bpf_single_step(&bpf_curr, &f[bpf_curr.Pc], pkt, pkt_caplen, + pkt_len); + bpf_curr.Pc++; + } + + return stop ? -1 : bpf_curr.R; +} + +static bool pcap_loaded(void) +{ + if (pcap_fd < 0) + rl_printf("no pcap file loaded!\n"); + + return pcap_fd >= 0; +} + +static struct pcap_pkthdr *pcap_curr_pkt(void) +{ + return (void *) pcap_ptr_va_curr; +} + +static bool pcap_next_pkt(void) +{ + struct pcap_pkthdr *hdr = pcap_curr_pkt(); + + if (pcap_ptr_va_curr + sizeof(*hdr) - + pcap_ptr_va_start >= pcap_map_size) + return false; + if (hdr->caplen == 0 || hdr->len == 0 || hdr->caplen > hdr->len) + return false; + if (pcap_ptr_va_curr + sizeof(*hdr) + hdr->caplen - + pcap_ptr_va_start >= pcap_map_size) + return false; + + pcap_ptr_va_curr += (sizeof(*hdr) + hdr->caplen); + return true; +} + +static void pcap_reset_pkt(void) +{ + pcap_ptr_va_curr = pcap_ptr_va_start + sizeof(struct pcap_filehdr); +} + +static int try_load_pcap(const char *file) +{ + struct pcap_filehdr *hdr; + struct stat sb; + int ret; + + pcap_fd = open(file, O_RDONLY); + if (pcap_fd < 0) { + rl_printf("cannot open pcap [%s]!\n", strerror(errno)); + return CMD_ERR; + } + + ret = fstat(pcap_fd, &sb); + if (ret < 0) { + rl_printf("cannot fstat pcap file!\n"); + return CMD_ERR; + } + + if (!S_ISREG(sb.st_mode)) { + rl_printf("not a regular pcap file, duh!\n"); + return CMD_ERR; + } + + pcap_map_size = sb.st_size; + if (pcap_map_size <= sizeof(struct pcap_filehdr)) { + rl_printf("pcap file too small!\n"); + return CMD_ERR; + } + + pcap_ptr_va_start = mmap(NULL, pcap_map_size, PROT_READ, + MAP_SHARED | MAP_LOCKED, pcap_fd, 0); + if (pcap_ptr_va_start == MAP_FAILED) { + rl_printf("mmap of file failed!"); + return CMD_ERR; + } + + hdr = (void *) pcap_ptr_va_start; + if (hdr->magic != TCPDUMP_MAGIC) { + rl_printf("wrong pcap magic!\n"); + return CMD_ERR; + } + + pcap_reset_pkt(); + + return CMD_OK; + +} + +static void try_close_pcap(void) +{ + if (pcap_fd >= 0) { + munmap(pcap_ptr_va_start, pcap_map_size); + close(pcap_fd); + + pcap_ptr_va_start = pcap_ptr_va_curr = NULL; + pcap_map_size = 0; + pcap_packet = 0; + pcap_fd = -1; + } +} + +static int cmd_load_bpf(char *bpf_string) +{ + char sp, *token, separator = ','; + unsigned short bpf_len, i = 0; + struct sock_filter tmp; + + bpf_prog_len = 0; + memset(bpf_image, 0, sizeof(bpf_image)); + + if (sscanf(bpf_string, "%hu%c", &bpf_len, &sp) != 2 || + sp != separator || bpf_len > BPF_MAXINSNS || bpf_len == 0) { + rl_printf("syntax error in head length encoding!\n"); + return CMD_ERR; + } + + token = bpf_string; + while ((token = strchr(token, separator)) && (++token)[0]) { + if (i >= bpf_len) { + rl_printf("program exceeds encoded length!\n"); + return CMD_ERR; + } + + if (sscanf(token, "%hu %hhu %hhu %u,", + &tmp.code, &tmp.jt, &tmp.jf, &tmp.k) != 4) { + rl_printf("syntax error at instruction %d!\n", i); + return CMD_ERR; + } + + bpf_image[i].code = tmp.code; + bpf_image[i].jt = tmp.jt; + bpf_image[i].jf = tmp.jf; + bpf_image[i].k = tmp.k; + + i++; + } + + if (i != bpf_len) { + rl_printf("syntax error exceeding encoded length!\n"); + return CMD_ERR; + } else + bpf_prog_len = bpf_len; + if (!bpf_runnable(bpf_image, bpf_prog_len)) + bpf_prog_len = 0; + + return CMD_OK; +} + +static int cmd_load_pcap(char *file) +{ + char *file_trim, *tmp; + + file_trim = strtok_r(file, " ", &tmp); + if (file_trim == NULL) + return CMD_ERR; + + try_close_pcap(); + + return try_load_pcap(file_trim); +} + +static int cmd_load(char *arg) +{ + char *subcmd, *cont, *tmp = strdup(arg); + int ret = CMD_OK; + + subcmd = strtok_r(tmp, " ", &cont); + if (subcmd == NULL) + goto out; + if (matches(subcmd, "bpf") == 0) { + bpf_reset(); + bpf_reset_breakpoints(); + + ret = cmd_load_bpf(cont); + } else if (matches(subcmd, "pcap") == 0) { + ret = cmd_load_pcap(cont); + } else { +out: + rl_printf("bpf <code>: load bpf code\n"); + rl_printf("pcap <file>: load pcap file\n"); + ret = CMD_ERR; + } + + free(tmp); + return ret; +} + +static int cmd_step(char *num) +{ + struct pcap_pkthdr *hdr; + int steps, ret; + + if (!bpf_prog_loaded() || !pcap_loaded()) + return CMD_ERR; + + steps = strtol(num, NULL, 10); + if (steps == 0 || strlen(num) == 0) + steps = 1; + if (steps < 0) { + if (!bpf_restore_regs(steps)) + return CMD_ERR; + steps = 1; + } + + hdr = pcap_curr_pkt(); + ret = bpf_run_stepping(bpf_image, bpf_prog_len, + (uint8_t *) hdr + sizeof(*hdr), + hdr->caplen, hdr->len, steps); + if (ret >= 0 || bpf_curr.Rs) { + bpf_reset(); + if (!pcap_next_pkt()) { + rl_printf("(going back to first packet)\n"); + pcap_reset_pkt(); + } else { + rl_printf("(next packet)\n"); + } + } + + return CMD_OK; +} + +static int cmd_select(char *num) +{ + unsigned int which, i; + bool have_next = true; + + if (!pcap_loaded() || strlen(num) == 0) + return CMD_ERR; + + which = strtoul(num, NULL, 10); + if (which == 0) { + rl_printf("packet count starts with 1, clamping!\n"); + which = 1; + } + + pcap_reset_pkt(); + bpf_reset(); + + for (i = 0; i < which && (have_next = pcap_next_pkt()); i++) + /* noop */; + if (!have_next || pcap_curr_pkt() == NULL) { + rl_printf("no packet #%u available!\n", which); + pcap_reset_pkt(); + return CMD_ERR; + } + + return CMD_OK; +} + +static int cmd_breakpoint(char *subcmd) +{ + if (!bpf_prog_loaded()) + return CMD_ERR; + if (strlen(subcmd) == 0) + bpf_dump_breakpoints(); + else if (matches(subcmd, "reset") == 0) + bpf_reset_breakpoints(); + else { + unsigned int where = strtoul(subcmd, NULL, 10); + + if (where < bpf_prog_len) { + bpf_set_breakpoints(where); + rl_printf("breakpoint at: "); + bpf_disasm(bpf_image[where], where); + } + } + + return CMD_OK; +} + +static int cmd_run(char *num) +{ + static uint32_t pass = 0, fail = 0; + bool has_limit = true; + int pkts = 0, i = 0; + + if (!bpf_prog_loaded() || !pcap_loaded()) + return CMD_ERR; + + pkts = strtol(num, NULL, 10); + if (pkts == 0 || strlen(num) == 0) + has_limit = false; + + do { + struct pcap_pkthdr *hdr = pcap_curr_pkt(); + int ret = bpf_run_all(bpf_image, bpf_prog_len, + (uint8_t *) hdr + sizeof(*hdr), + hdr->caplen, hdr->len); + if (ret > 0) + pass++; + else if (ret == 0) + fail++; + else + return CMD_OK; + bpf_reset(); + } while (pcap_next_pkt() && (!has_limit || (has_limit && ++i < pkts))); + + rl_printf("bpf passes:%u fails:%u\n", pass, fail); + + pcap_reset_pkt(); + bpf_reset(); + + pass = fail = 0; + return CMD_OK; +} + +static int cmd_disassemble(char *line_string) +{ + bool single_line = false; + unsigned long line; + + if (!bpf_prog_loaded()) + return CMD_ERR; + if (strlen(line_string) > 0 && + (line = strtoul(line_string, NULL, 10)) < bpf_prog_len) + single_line = true; + if (single_line) + bpf_disasm(bpf_image[line], line); + else + bpf_disasm_all(bpf_image, bpf_prog_len); + + return CMD_OK; +} + +static int cmd_dump(char *dontcare) +{ + if (!bpf_prog_loaded()) + return CMD_ERR; + + bpf_dump_all(bpf_image, bpf_prog_len); + + return CMD_OK; +} + +static int cmd_quit(char *dontcare) +{ + return CMD_EX; +} + +static const struct shell_cmd cmds[] = { + { .name = "load", .func = cmd_load }, + { .name = "select", .func = cmd_select }, + { .name = "step", .func = cmd_step }, + { .name = "run", .func = cmd_run }, + { .name = "breakpoint", .func = cmd_breakpoint }, + { .name = "disassemble", .func = cmd_disassemble }, + { .name = "dump", .func = cmd_dump }, + { .name = "quit", .func = cmd_quit }, +}; + +static int execf(char *arg) +{ + char *cmd, *cont, *tmp = strdup(arg); + int i, ret = 0, len; + + cmd = strtok_r(tmp, " ", &cont); + if (cmd == NULL) + goto out; + len = strlen(cmd); + for (i = 0; i < array_size(cmds); i++) { + if (len != strlen(cmds[i].name)) + continue; + if (strncmp(cmds[i].name, cmd, len) == 0) { + ret = cmds[i].func(cont); + break; + } + } +out: + free(tmp); + return ret; +} + +static char *shell_comp_gen(const char *buf, int state) +{ + static int list_index, len; + + if (!state) { + list_index = 0; + len = strlen(buf); + } + + for (; list_index < array_size(cmds); ) { + const char *name = cmds[list_index].name; + + list_index++; + if (strncmp(name, buf, len) == 0) + return strdup(name); + } + + return NULL; +} + +static char **shell_completion(const char *buf, int start, int end) +{ + char **matches = NULL; + + if (start == 0) + matches = rl_completion_matches(buf, shell_comp_gen); + + return matches; +} + +static void intr_shell(int sig) +{ + if (rl_end) + rl_kill_line(-1, 0); + + rl_crlf(); + rl_refresh_line(0, 0); + rl_free_line_state(); +} + +static void init_shell(FILE *fin, FILE *fout) +{ + char file[128]; + + snprintf(file, sizeof(file), "%s/.bpf_dbg_history", getenv("HOME")); + read_history(file); + + rl_instream = fin; + rl_outstream = fout; + + rl_readline_name = "bpf_dbg"; + rl_terminal_name = getenv("TERM"); + + rl_catch_signals = 0; + rl_catch_sigwinch = 1; + + rl_attempted_completion_function = shell_completion; + + rl_bind_key('\t', rl_complete); + + rl_bind_key_in_map('\t', rl_complete, emacs_meta_keymap); + rl_bind_key_in_map('\033', rl_complete, emacs_meta_keymap); + + snprintf(file, sizeof(file), "%s/.bpf_dbg_init", getenv("HOME")); + rl_read_init_file(file); + + rl_prep_terminal(0); + rl_set_signals(); + + signal(SIGINT, intr_shell); +} + +static void exit_shell(FILE *fin, FILE *fout) +{ + char file[128]; + + snprintf(file, sizeof(file), "%s/.bpf_dbg_history", getenv("HOME")); + write_history(file); + + clear_history(); + rl_deprep_terminal(); + + try_close_pcap(); + + if (fin != stdin) + fclose(fin); + if (fout != stdout) + fclose(fout); +} + +static int run_shell_loop(FILE *fin, FILE *fout) +{ + char *buf; + + init_shell(fin, fout); + + while ((buf = readline("> ")) != NULL) { + int ret = execf(buf); + if (ret == CMD_EX) + break; + if (ret == CMD_OK && strlen(buf) > 0) + add_history(buf); + + free(buf); + } + + exit_shell(fin, fout); + return 0; +} + +int main(int argc, char **argv) +{ + FILE *fin = NULL, *fout = NULL; + + if (argc >= 2) + fin = fopen(argv[1], "r"); + if (argc >= 3) + fout = fopen(argv[2], "w"); + + return run_shell_loop(fin ? : stdin, fout ? : stdout); +} diff --git a/kernel/tools/net/bpf_exp.l b/kernel/tools/net/bpf_exp.l new file mode 100644 index 000000000..7cc72a336 --- /dev/null +++ b/kernel/tools/net/bpf_exp.l @@ -0,0 +1,146 @@ +/* + * BPF asm code lexer + * + * This program is free software; you can distribute it and/or modify + * it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, + * or (at your option) any later version. + * + * Syntax kept close to: + * + * Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new + * architecture for user-level packet capture. In Proceedings of the + * USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993 + * Conference Proceedings (USENIX'93). USENIX Association, Berkeley, + * CA, USA, 2-2. + * + * Copyright 2013 Daniel Borkmann <borkmann@redhat.com> + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +%{ + +#include <stdio.h> +#include <stdint.h> +#include <stdlib.h> + +#include "bpf_exp.yacc.h" + +extern void yyerror(const char *str); + +%} + +%option align +%option ecs + +%option nounput +%option noreject +%option noinput +%option noyywrap + +%option 8bit +%option caseless +%option yylineno + +%% + +"ldb" { return OP_LDB; } +"ldh" { return OP_LDH; } +"ld" { return OP_LD; } +"ldi" { return OP_LDI; } +"ldx" { return OP_LDX; } +"ldxi" { return OP_LDXI; } +"ldxb" { return OP_LDXB; } +"st" { return OP_ST; } +"stx" { return OP_STX; } +"jmp" { return OP_JMP; } +"ja" { return OP_JMP; } +"jeq" { return OP_JEQ; } +"jneq" { return OP_JNEQ; } +"jne" { return OP_JNEQ; } +"jlt" { return OP_JLT; } +"jle" { return OP_JLE; } +"jgt" { return OP_JGT; } +"jge" { return OP_JGE; } +"jset" { return OP_JSET; } +"add" { return OP_ADD; } +"sub" { return OP_SUB; } +"mul" { return OP_MUL; } +"div" { return OP_DIV; } +"mod" { return OP_MOD; } +"neg" { return OP_NEG; } +"and" { return OP_AND; } +"xor" { return OP_XOR; } +"or" { return OP_OR; } +"lsh" { return OP_LSH; } +"rsh" { return OP_RSH; } +"ret" { return OP_RET; } +"tax" { return OP_TAX; } +"txa" { return OP_TXA; } + +"#"?("len") { return K_PKT_LEN; } +"#"?("proto") { return K_PROTO; } +"#"?("type") { return K_TYPE; } +"#"?("poff") { return K_POFF; } +"#"?("ifidx") { return K_IFIDX; } +"#"?("nla") { return K_NLATTR; } +"#"?("nlan") { return K_NLATTR_NEST; } +"#"?("mark") { return K_MARK; } +"#"?("queue") { return K_QUEUE; } +"#"?("hatype") { return K_HATYPE; } +"#"?("rxhash") { return K_RXHASH; } +"#"?("cpu") { return K_CPU; } +"#"?("vlan_tci") { return K_VLAN_TCI; } +"#"?("vlan_pr") { return K_VLAN_AVAIL; } +"#"?("vlan_avail") { return K_VLAN_AVAIL; } +"#"?("vlan_tpid") { return K_VLAN_TPID; } +"#"?("rand") { return K_RAND; } + +":" { return ':'; } +"," { return ','; } +"#" { return '#'; } +"%" { return '%'; } +"[" { return '['; } +"]" { return ']'; } +"(" { return '('; } +")" { return ')'; } +"x" { return 'x'; } +"a" { return 'a'; } +"+" { return '+'; } +"M" { return 'M'; } +"*" { return '*'; } +"&" { return '&'; } + +([0][x][a-fA-F0-9]+) { + yylval.number = strtoul(yytext, NULL, 16); + return number; + } +([0][b][0-1]+) { + yylval.number = strtol(yytext + 2, NULL, 2); + return number; + } +(([0])|([-+]?[1-9][0-9]*)) { + yylval.number = strtol(yytext, NULL, 10); + return number; + } +([0][0-9]+) { + yylval.number = strtol(yytext + 1, NULL, 8); + return number; + } +[a-zA-Z_][a-zA-Z0-9_]+ { + yylval.label = strdup(yytext); + return label; + } + +"/*"([^\*]|\*[^/])*"*/" { /* NOP */ } +";"[^\n]* { /* NOP */ } +^#.* { /* NOP */ } +[ \t]+ { /* NOP */ } +[ \n]+ { /* NOP */ } + +. { + printf("unknown character \'%s\'", yytext); + yyerror("lex unknown character"); + } + +%% diff --git a/kernel/tools/net/bpf_exp.y b/kernel/tools/net/bpf_exp.y new file mode 100644 index 000000000..e24eea1b0 --- /dev/null +++ b/kernel/tools/net/bpf_exp.y @@ -0,0 +1,780 @@ +/* + * BPF asm code parser + * + * This program is free software; you can distribute it and/or modify + * it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, + * or (at your option) any later version. + * + * Syntax kept close to: + * + * Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new + * architecture for user-level packet capture. In Proceedings of the + * USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993 + * Conference Proceedings (USENIX'93). USENIX Association, Berkeley, + * CA, USA, 2-2. + * + * Copyright 2013 Daniel Borkmann <borkmann@redhat.com> + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +%{ + +#include <stdio.h> +#include <string.h> +#include <stdint.h> +#include <stdlib.h> +#include <stdbool.h> +#include <unistd.h> +#include <errno.h> +#include <assert.h> +#include <linux/filter.h> + +#include "bpf_exp.yacc.h" + +enum jmp_type { JTL, JFL, JKL }; + +extern FILE *yyin; +extern int yylex(void); +extern void yyerror(const char *str); + +extern void bpf_asm_compile(FILE *fp, bool cstyle); +static void bpf_set_curr_instr(uint16_t op, uint8_t jt, uint8_t jf, uint32_t k); +static void bpf_set_curr_label(char *label); +static void bpf_set_jmp_label(char *label, enum jmp_type type); + +%} + +%union { + char *label; + uint32_t number; +} + +%token OP_LDB OP_LDH OP_LD OP_LDX OP_ST OP_STX OP_JMP OP_JEQ OP_JGT OP_JGE +%token OP_JSET OP_ADD OP_SUB OP_MUL OP_DIV OP_AND OP_OR OP_XOR OP_LSH OP_RSH +%token OP_RET OP_TAX OP_TXA OP_LDXB OP_MOD OP_NEG OP_JNEQ OP_JLT OP_JLE OP_LDI +%token OP_LDXI + +%token K_PKT_LEN K_PROTO K_TYPE K_NLATTR K_NLATTR_NEST K_MARK K_QUEUE K_HATYPE +%token K_RXHASH K_CPU K_IFIDX K_VLAN_TCI K_VLAN_AVAIL K_VLAN_TPID K_POFF K_RAND + +%token ':' ',' '[' ']' '(' ')' 'x' 'a' '+' 'M' '*' '&' '#' '%' + +%token number label + +%type <label> label +%type <number> number + +%% + +prog + : line + | prog line + ; + +line + : instr + | labelled_instr + ; + +labelled_instr + : labelled instr + ; + +instr + : ldb + | ldh + | ld + | ldi + | ldx + | ldxi + | st + | stx + | jmp + | jeq + | jneq + | jlt + | jle + | jgt + | jge + | jset + | add + | sub + | mul + | div + | mod + | neg + | and + | or + | xor + | lsh + | rsh + | ret + | tax + | txa + ; + +labelled + : label ':' { bpf_set_curr_label($1); } + ; + +ldb + : OP_LDB '[' 'x' '+' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $5); } + | OP_LDB '[' '%' 'x' '+' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_IND, 0, 0, $6); } + | OP_LDB '[' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, $3); } + | OP_LDB K_PROTO { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PROTOCOL); } + | OP_LDB K_TYPE { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PKTTYPE); } + | OP_LDB K_IFIDX { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_IFINDEX); } + | OP_LDB K_NLATTR { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_NLATTR); } + | OP_LDB K_NLATTR_NEST { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_NLATTR_NEST); } + | OP_LDB K_MARK { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_MARK); } + | OP_LDB K_QUEUE { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_QUEUE); } + | OP_LDB K_HATYPE { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_HATYPE); } + | OP_LDB K_RXHASH { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_RXHASH); } + | OP_LDB K_CPU { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_CPU); } + | OP_LDB K_VLAN_TCI { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TAG); } + | OP_LDB K_VLAN_AVAIL { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); } + | OP_LDB K_POFF { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PAY_OFFSET); } + | OP_LDB K_RAND { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_RANDOM); } + | OP_LDB K_VLAN_TPID { + bpf_set_curr_instr(BPF_LD | BPF_B | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TPID); } + ; + +ldh + : OP_LDH '[' 'x' '+' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $5); } + | OP_LDH '[' '%' 'x' '+' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_IND, 0, 0, $6); } + | OP_LDH '[' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, $3); } + | OP_LDH K_PROTO { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PROTOCOL); } + | OP_LDH K_TYPE { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PKTTYPE); } + | OP_LDH K_IFIDX { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_IFINDEX); } + | OP_LDH K_NLATTR { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_NLATTR); } + | OP_LDH K_NLATTR_NEST { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_NLATTR_NEST); } + | OP_LDH K_MARK { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_MARK); } + | OP_LDH K_QUEUE { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_QUEUE); } + | OP_LDH K_HATYPE { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_HATYPE); } + | OP_LDH K_RXHASH { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_RXHASH); } + | OP_LDH K_CPU { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_CPU); } + | OP_LDH K_VLAN_TCI { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TAG); } + | OP_LDH K_VLAN_AVAIL { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); } + | OP_LDH K_POFF { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PAY_OFFSET); } + | OP_LDH K_RAND { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_RANDOM); } + | OP_LDH K_VLAN_TPID { + bpf_set_curr_instr(BPF_LD | BPF_H | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TPID); } + ; + +ldi + : OP_LDI '#' number { + bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); } + | OP_LDI number { + bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $2); } + ; + +ld + : OP_LD '#' number { + bpf_set_curr_instr(BPF_LD | BPF_IMM, 0, 0, $3); } + | OP_LD K_PKT_LEN { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_LEN, 0, 0, 0); } + | OP_LD K_PROTO { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PROTOCOL); } + | OP_LD K_TYPE { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PKTTYPE); } + | OP_LD K_IFIDX { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_IFINDEX); } + | OP_LD K_NLATTR { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_NLATTR); } + | OP_LD K_NLATTR_NEST { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_NLATTR_NEST); } + | OP_LD K_MARK { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_MARK); } + | OP_LD K_QUEUE { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_QUEUE); } + | OP_LD K_HATYPE { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_HATYPE); } + | OP_LD K_RXHASH { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_RXHASH); } + | OP_LD K_CPU { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_CPU); } + | OP_LD K_VLAN_TCI { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TAG); } + | OP_LD K_VLAN_AVAIL { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT); } + | OP_LD K_POFF { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_PAY_OFFSET); } + | OP_LD K_RAND { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_RANDOM); } + | OP_LD K_VLAN_TPID { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, + SKF_AD_OFF + SKF_AD_VLAN_TPID); } + | OP_LD 'M' '[' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_MEM, 0, 0, $4); } + | OP_LD '[' 'x' '+' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $5); } + | OP_LD '[' '%' 'x' '+' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_IND, 0, 0, $6); } + | OP_LD '[' number ']' { + bpf_set_curr_instr(BPF_LD | BPF_W | BPF_ABS, 0, 0, $3); } + ; + +ldxi + : OP_LDXI '#' number { + bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); } + | OP_LDXI number { + bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $2); } + ; + +ldx + : OP_LDX '#' number { + bpf_set_curr_instr(BPF_LDX | BPF_IMM, 0, 0, $3); } + | OP_LDX K_PKT_LEN { + bpf_set_curr_instr(BPF_LDX | BPF_W | BPF_LEN, 0, 0, 0); } + | OP_LDX 'M' '[' number ']' { + bpf_set_curr_instr(BPF_LDX | BPF_MEM, 0, 0, $4); } + | OP_LDXB number '*' '(' '[' number ']' '&' number ')' { + if ($2 != 4 || $9 != 0xf) { + fprintf(stderr, "ldxb offset not supported!\n"); + exit(0); + } else { + bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } } + | OP_LDX number '*' '(' '[' number ']' '&' number ')' { + if ($2 != 4 || $9 != 0xf) { + fprintf(stderr, "ldxb offset not supported!\n"); + exit(0); + } else { + bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } } + ; + +st + : OP_ST 'M' '[' number ']' { + bpf_set_curr_instr(BPF_ST, 0, 0, $4); } + ; + +stx + : OP_STX 'M' '[' number ']' { + bpf_set_curr_instr(BPF_STX, 0, 0, $4); } + ; + +jmp + : OP_JMP label { + bpf_set_jmp_label($2, JKL); + bpf_set_curr_instr(BPF_JMP | BPF_JA, 0, 0, 0); } + ; + +jeq + : OP_JEQ '#' number ',' label ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_jmp_label($7, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); } + | OP_JEQ 'x' ',' label ',' label { + bpf_set_jmp_label($4, JTL); + bpf_set_jmp_label($6, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } + | OP_JEQ '%' 'x' ',' label ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_jmp_label($7, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } + | OP_JEQ '#' number ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); } + | OP_JEQ 'x' ',' label { + bpf_set_jmp_label($4, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } + | OP_JEQ '%' 'x' ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } + ; + +jneq + : OP_JNEQ '#' number ',' label { + bpf_set_jmp_label($5, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_K, 0, 0, $3); } + | OP_JNEQ 'x' ',' label { + bpf_set_jmp_label($4, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } + | OP_JNEQ '%' 'x' ',' label { + bpf_set_jmp_label($5, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JEQ | BPF_X, 0, 0, 0); } + ; + +jlt + : OP_JLT '#' number ',' label { + bpf_set_jmp_label($5, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); } + | OP_JLT 'x' ',' label { + bpf_set_jmp_label($4, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } + | OP_JLT '%' 'x' ',' label { + bpf_set_jmp_label($5, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } + ; + +jle + : OP_JLE '#' number ',' label { + bpf_set_jmp_label($5, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); } + | OP_JLE 'x' ',' label { + bpf_set_jmp_label($4, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } + | OP_JLE '%' 'x' ',' label { + bpf_set_jmp_label($5, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } + ; + +jgt + : OP_JGT '#' number ',' label ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_jmp_label($7, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); } + | OP_JGT 'x' ',' label ',' label { + bpf_set_jmp_label($4, JTL); + bpf_set_jmp_label($6, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } + | OP_JGT '%' 'x' ',' label ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_jmp_label($7, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } + | OP_JGT '#' number ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_K, 0, 0, $3); } + | OP_JGT 'x' ',' label { + bpf_set_jmp_label($4, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } + | OP_JGT '%' 'x' ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JGT | BPF_X, 0, 0, 0); } + ; + +jge + : OP_JGE '#' number ',' label ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_jmp_label($7, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); } + | OP_JGE 'x' ',' label ',' label { + bpf_set_jmp_label($4, JTL); + bpf_set_jmp_label($6, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } + | OP_JGE '%' 'x' ',' label ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_jmp_label($7, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } + | OP_JGE '#' number ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_K, 0, 0, $3); } + | OP_JGE 'x' ',' label { + bpf_set_jmp_label($4, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } + | OP_JGE '%' 'x' ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JGE | BPF_X, 0, 0, 0); } + ; + +jset + : OP_JSET '#' number ',' label ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_jmp_label($7, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); } + | OP_JSET 'x' ',' label ',' label { + bpf_set_jmp_label($4, JTL); + bpf_set_jmp_label($6, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); } + | OP_JSET '%' 'x' ',' label ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_jmp_label($7, JFL); + bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); } + | OP_JSET '#' number ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_K, 0, 0, $3); } + | OP_JSET 'x' ',' label { + bpf_set_jmp_label($4, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); } + | OP_JSET '%' 'x' ',' label { + bpf_set_jmp_label($5, JTL); + bpf_set_curr_instr(BPF_JMP | BPF_JSET | BPF_X, 0, 0, 0); } + ; + +add + : OP_ADD '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_K, 0, 0, $3); } + | OP_ADD 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); } + | OP_ADD '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_ADD | BPF_X, 0, 0, 0); } + ; + +sub + : OP_SUB '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_K, 0, 0, $3); } + | OP_SUB 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); } + | OP_SUB '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_SUB | BPF_X, 0, 0, 0); } + ; + +mul + : OP_MUL '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_K, 0, 0, $3); } + | OP_MUL 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); } + | OP_MUL '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_MUL | BPF_X, 0, 0, 0); } + ; + +div + : OP_DIV '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_K, 0, 0, $3); } + | OP_DIV 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); } + | OP_DIV '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_DIV | BPF_X, 0, 0, 0); } + ; + +mod + : OP_MOD '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_K, 0, 0, $3); } + | OP_MOD 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); } + | OP_MOD '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_MOD | BPF_X, 0, 0, 0); } + ; + +neg + : OP_NEG { + bpf_set_curr_instr(BPF_ALU | BPF_NEG, 0, 0, 0); } + ; + +and + : OP_AND '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_K, 0, 0, $3); } + | OP_AND 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); } + | OP_AND '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_AND | BPF_X, 0, 0, 0); } + ; + +or + : OP_OR '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_K, 0, 0, $3); } + | OP_OR 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); } + | OP_OR '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_OR | BPF_X, 0, 0, 0); } + ; + +xor + : OP_XOR '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_K, 0, 0, $3); } + | OP_XOR 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); } + | OP_XOR '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_XOR | BPF_X, 0, 0, 0); } + ; + +lsh + : OP_LSH '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_K, 0, 0, $3); } + | OP_LSH 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); } + | OP_LSH '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_LSH | BPF_X, 0, 0, 0); } + ; + +rsh + : OP_RSH '#' number { + bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_K, 0, 0, $3); } + | OP_RSH 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); } + | OP_RSH '%' 'x' { + bpf_set_curr_instr(BPF_ALU | BPF_RSH | BPF_X, 0, 0, 0); } + ; + +ret + : OP_RET 'a' { + bpf_set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); } + | OP_RET '%' 'a' { + bpf_set_curr_instr(BPF_RET | BPF_A, 0, 0, 0); } + | OP_RET 'x' { + bpf_set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); } + | OP_RET '%' 'x' { + bpf_set_curr_instr(BPF_RET | BPF_X, 0, 0, 0); } + | OP_RET '#' number { + bpf_set_curr_instr(BPF_RET | BPF_K, 0, 0, $3); } + ; + +tax + : OP_TAX { + bpf_set_curr_instr(BPF_MISC | BPF_TAX, 0, 0, 0); } + ; + +txa + : OP_TXA { + bpf_set_curr_instr(BPF_MISC | BPF_TXA, 0, 0, 0); } + ; + +%% + +static int curr_instr = 0; +static struct sock_filter out[BPF_MAXINSNS]; +static char **labels, **labels_jt, **labels_jf, **labels_k; + +static void bpf_assert_max(void) +{ + if (curr_instr >= BPF_MAXINSNS) { + fprintf(stderr, "only max %u insns allowed!\n", BPF_MAXINSNS); + exit(0); + } +} + +static void bpf_set_curr_instr(uint16_t code, uint8_t jt, uint8_t jf, + uint32_t k) +{ + bpf_assert_max(); + out[curr_instr].code = code; + out[curr_instr].jt = jt; + out[curr_instr].jf = jf; + out[curr_instr].k = k; + curr_instr++; +} + +static void bpf_set_curr_label(char *label) +{ + bpf_assert_max(); + labels[curr_instr] = label; +} + +static void bpf_set_jmp_label(char *label, enum jmp_type type) +{ + bpf_assert_max(); + switch (type) { + case JTL: + labels_jt[curr_instr] = label; + break; + case JFL: + labels_jf[curr_instr] = label; + break; + case JKL: + labels_k[curr_instr] = label; + break; + } +} + +static int bpf_find_insns_offset(const char *label) +{ + int i, max = curr_instr, ret = -ENOENT; + + for (i = 0; i < max; i++) { + if (labels[i] && !strcmp(label, labels[i])) { + ret = i; + break; + } + } + + if (ret == -ENOENT) { + fprintf(stderr, "no such label \'%s\'!\n", label); + exit(0); + } + + return ret; +} + +static void bpf_stage_1_insert_insns(void) +{ + yyparse(); +} + +static void bpf_reduce_k_jumps(void) +{ + int i; + + for (i = 0; i < curr_instr; i++) { + if (labels_k[i]) { + int off = bpf_find_insns_offset(labels_k[i]); + out[i].k = (uint32_t) (off - i - 1); + } + } +} + +static void bpf_reduce_jt_jumps(void) +{ + int i; + + for (i = 0; i < curr_instr; i++) { + if (labels_jt[i]) { + int off = bpf_find_insns_offset(labels_jt[i]); + out[i].jt = (uint8_t) (off - i -1); + } + } +} + +static void bpf_reduce_jf_jumps(void) +{ + int i; + + for (i = 0; i < curr_instr; i++) { + if (labels_jf[i]) { + int off = bpf_find_insns_offset(labels_jf[i]); + out[i].jf = (uint8_t) (off - i - 1); + } + } +} + +static void bpf_stage_2_reduce_labels(void) +{ + bpf_reduce_k_jumps(); + bpf_reduce_jt_jumps(); + bpf_reduce_jf_jumps(); +} + +static void bpf_pretty_print_c(void) +{ + int i; + + for (i = 0; i < curr_instr; i++) + printf("{ %#04x, %2u, %2u, %#010x },\n", out[i].code, + out[i].jt, out[i].jf, out[i].k); +} + +static void bpf_pretty_print(void) +{ + int i; + + printf("%u,", curr_instr); + for (i = 0; i < curr_instr; i++) + printf("%u %u %u %u,", out[i].code, + out[i].jt, out[i].jf, out[i].k); + printf("\n"); +} + +static void bpf_init(void) +{ + memset(out, 0, sizeof(out)); + + labels = calloc(BPF_MAXINSNS, sizeof(*labels)); + assert(labels); + labels_jt = calloc(BPF_MAXINSNS, sizeof(*labels_jt)); + assert(labels_jt); + labels_jf = calloc(BPF_MAXINSNS, sizeof(*labels_jf)); + assert(labels_jf); + labels_k = calloc(BPF_MAXINSNS, sizeof(*labels_k)); + assert(labels_k); +} + +static void bpf_destroy_labels(void) +{ + int i; + + for (i = 0; i < curr_instr; i++) { + free(labels_jf[i]); + free(labels_jt[i]); + free(labels_k[i]); + free(labels[i]); + } +} + +static void bpf_destroy(void) +{ + bpf_destroy_labels(); + free(labels_jt); + free(labels_jf); + free(labels_k); + free(labels); +} + +void bpf_asm_compile(FILE *fp, bool cstyle) +{ + yyin = fp; + + bpf_init(); + bpf_stage_1_insert_insns(); + bpf_stage_2_reduce_labels(); + bpf_destroy(); + + if (cstyle) + bpf_pretty_print_c(); + else + bpf_pretty_print(); + + if (fp != stdin) + fclose(yyin); +} + +void yyerror(const char *str) +{ + exit(1); +} diff --git a/kernel/tools/net/bpf_jit_disasm.c b/kernel/tools/net/bpf_jit_disasm.c new file mode 100644 index 000000000..618c2bcd4 --- /dev/null +++ b/kernel/tools/net/bpf_jit_disasm.c @@ -0,0 +1,199 @@ +/* + * Minimal BPF JIT image disassembler + * + * Disassembles BPF JIT compiler emitted opcodes back to asm insn's for + * debugging or verification purposes. + * + * To get the disassembly of the JIT code, do the following: + * + * 1) `echo 2 > /proc/sys/net/core/bpf_jit_enable` + * 2) Load a BPF filter (e.g. `tcpdump -p -n -s 0 -i eth1 host 192.168.20.0/24`) + * 3) Run e.g. `bpf_jit_disasm -o` to read out the last JIT code + * + * Copyright 2013 Daniel Borkmann <borkmann@redhat.com> + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <assert.h> +#include <unistd.h> +#include <string.h> +#include <bfd.h> +#include <dis-asm.h> +#include <sys/klog.h> +#include <sys/types.h> +#include <regex.h> + +static void get_exec_path(char *tpath, size_t size) +{ + char *path; + ssize_t len; + + snprintf(tpath, size, "/proc/%d/exe", (int) getpid()); + tpath[size - 1] = 0; + + path = strdup(tpath); + assert(path); + + len = readlink(path, tpath, size); + tpath[len] = 0; + + free(path); +} + +static void get_asm_insns(uint8_t *image, size_t len, int opcodes) +{ + int count, i, pc = 0; + char tpath[256]; + struct disassemble_info info; + disassembler_ftype disassemble; + bfd *bfdf; + + memset(tpath, 0, sizeof(tpath)); + get_exec_path(tpath, sizeof(tpath)); + + bfdf = bfd_openr(tpath, NULL); + assert(bfdf); + assert(bfd_check_format(bfdf, bfd_object)); + + init_disassemble_info(&info, stdout, (fprintf_ftype) fprintf); + info.arch = bfd_get_arch(bfdf); + info.mach = bfd_get_mach(bfdf); + info.buffer = image; + info.buffer_length = len; + + disassemble_init_for_target(&info); + + disassemble = disassembler(bfdf); + assert(disassemble); + + do { + printf("%4x:\t", pc); + + count = disassemble(pc, &info); + + if (opcodes) { + printf("\n\t"); + for (i = 0; i < count; ++i) + printf("%02x ", (uint8_t) image[pc + i]); + } + printf("\n"); + + pc += count; + } while(count > 0 && pc < len); + + bfd_close(bfdf); +} + +static char *get_klog_buff(int *klen) +{ + int ret, len = klogctl(10, NULL, 0); + char *buff = malloc(len); + + assert(buff && klen); + ret = klogctl(3, buff, len); + assert(ret >= 0); + *klen = ret; + + return buff; +} + +static void put_klog_buff(char *buff) +{ + free(buff); +} + +static int get_last_jit_image(char *haystack, size_t hlen, + uint8_t *image, size_t ilen) +{ + char *ptr, *pptr, *tmp; + off_t off = 0; + int ret, flen, proglen, pass, ulen = 0; + regmatch_t pmatch[1]; + unsigned long base; + regex_t regex; + + if (hlen == 0) + return 0; + + ret = regcomp(®ex, "flen=[[:alnum:]]+ proglen=[[:digit:]]+ " + "pass=[[:digit:]]+ image=[[:xdigit:]]+", REG_EXTENDED); + assert(ret == 0); + + ptr = haystack; + memset(pmatch, 0, sizeof(pmatch)); + + while (1) { + ret = regexec(®ex, ptr, 1, pmatch, 0); + if (ret == 0) { + ptr += pmatch[0].rm_eo; + off += pmatch[0].rm_eo; + assert(off < hlen); + } else + break; + } + + ptr = haystack + off - (pmatch[0].rm_eo - pmatch[0].rm_so); + ret = sscanf(ptr, "flen=%d proglen=%d pass=%d image=%lx", + &flen, &proglen, &pass, &base); + if (ret != 4) + return 0; + + tmp = ptr = haystack + off; + while ((ptr = strtok(tmp, "\n")) != NULL && ulen < ilen) { + tmp = NULL; + if (!strstr(ptr, "JIT code")) + continue; + pptr = ptr; + while ((ptr = strstr(pptr, ":"))) + pptr = ptr + 1; + ptr = pptr; + do { + image[ulen++] = (uint8_t) strtoul(pptr, &pptr, 16); + if (ptr == pptr || ulen >= ilen) { + ulen--; + break; + } + ptr = pptr; + } while (1); + } + + assert(ulen == proglen); + printf("%d bytes emitted from JIT compiler (pass:%d, flen:%d)\n", + proglen, pass, flen); + printf("%lx + <x>:\n", base); + + regfree(®ex); + return ulen; +} + +int main(int argc, char **argv) +{ + int len, klen, opcodes = 0; + char *kbuff; + static uint8_t image[32768]; + + if (argc > 1) { + if (!strncmp("-o", argv[argc - 1], 2)) { + opcodes = 1; + } else { + printf("usage: bpf_jit_disasm [-o: show opcodes]\n"); + exit(0); + } + } + + bfd_init(); + memset(image, 0, sizeof(image)); + + kbuff = get_klog_buff(&klen); + + len = get_last_jit_image(kbuff, klen, image, sizeof(image)); + if (len > 0) + get_asm_insns(image, len, opcodes); + + put_klog_buff(kbuff); + + return 0; +} |