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// Copyright (c) Authors of Clover
//
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Apache License, Version 2.0
// which accompanies this distribution, and is available at
// http://www.apache.org/licenses/LICENSE-2.0
#include <uapi/linux/if_ether.h>
#include <uapi/linux/in.h>
#include <uapi/linux/ip.h>
#include <uapi/linux/tcp.h>
#include <uapi/linux/pkt_cls.h>
#include <uapi/linux/bpf.h>
#include <bcc/proto.h>
#define HTTP_HDR_MIN_LEN 7
#define MAX_SESSION_TABLE_ENTRIES 8192
typedef enum {
UNDEFINED = 0,
HTTP = 1,
HTTP2 = 2,
TCP = 3,
UDP = 4,
} app_proto_t;
typedef struct session_key_ {
u32 src_ip;
u32 dst_ip;
unsigned short src_port;
unsigned short dst_port;
} session_key_t;
typedef struct session_ {
u64 req_time;
u64 resp_time;
} session_t;
typedef struct egress_match_ {
u32 dst_ip;
unsigned short dst_port;
} egress_match_t;
typedef enum policy_action_ {
RECORD = 1,
} policy_action_t;
BPF_PERF_OUTPUT(skb_events);
BPF_HASH(dports2proto, u16, u32);
BPF_HASH(egress_lookup_table, egress_match_t, policy_action_t);
BPF_HASH(sessions, session_key_t, session_t, MAX_SESSION_TABLE_ENTRIES);
struct eth_hdr {
unsigned char h_dest[ETH_ALEN];
unsigned char h_source[ETH_ALEN];
unsigned short h_proto;
};
static inline int ipv4_hdrlen(struct iphdr *ip4)
{
return ip4->ihl * 4;
}
static inline int tcp_doff(struct tcphdr *tcp_hdr)
{
return tcp_hdr->doff * 4;
}
static inline int http_parsing(void *data, void *data_end)
{
int is_http = 1;
if (data + HTTP_HDR_MIN_LEN > data_end) {
bpf_trace_printk("No HTTP Header in TCP segment");
return 0;
}
if (strncmp((char*)data, "HTTP", 4)) {
if (strncmp((char*)data, "GET", 3)) {
if (strncmp((char*)data, "POST", 4)) {
if (strncmp((char*)data, "PUT", 3)) {
if (strncmp((char*)data, "HEAD", 4)) {
is_http = 0;
}
}
}
}
}
return is_http;
}
static inline void fill_up_sess_key(session_key_t *key, u32 src_ip,
u32 dst_ip, u16 src_port, u16 dst_port)
{
key->src_ip = src_ip;
key->dst_ip = dst_ip;
key->src_port = src_port;
key->dst_port = dst_port;
}
static inline int process_response(u32 src_ip, u32 dst_ip, u16 src_port,
u16 dst_port)
{
session_key_t sess_key = {};
session_t *session_ptr = NULL;
fill_up_sess_key(&sess_key, src_ip, dst_ip, src_port, dst_port);
session_ptr = sessions.lookup(&sess_key);
if (session_ptr != NULL) {
u64 resp_time = bpf_ktime_get_ns();
session_t update_session = {
session_ptr->req_time,
resp_time
};
sessions.update(&sess_key, &update_session);
return 1;
}
return 0;
}
static inline void process_request(u32 src_ip, u32 dst_ip, u16 src_port,
u16 dst_port)
{
session_key_t sess_key = {};
session_t *session_ptr = NULL;
session_t new_session = {
bpf_ktime_get_ns(),
0
};
fill_up_sess_key(&sess_key, src_ip, dst_ip, src_port, dst_port);
session_ptr = sessions.lookup(&sess_key);
if (! session_ptr) {
sessions.insert(&sess_key, &new_session);
}
/*
if (session_ptr != NULL) {
sessions.update(&sess_key, &new_session);
} else {
sessions.insert(&sess_key, &new_session);
}
*/
}
static inline app_proto_t ingress_tcp_parsing(struct tcphdr *tcp_hdr,
struct iphdr *ipv4_hdr,
void *data_end)
{
unsigned short dest_port = htons(tcp_hdr->dest);
egress_match_t egress_match = {};
policy_action_t *policy_ptr = NULL;
app_proto_t ret = TCP;
unsigned int *proto = dports2proto.lookup(&dest_port);
if (proto != NULL) {
/*
if (tcp_hdr->syn && !tcp_hdr->ack) {
return ret;
}
*/
ret = HTTP;
if (tcp_hdr->fin || tcp_hdr->rst) {
process_response(ntohl(ipv4_hdr->saddr),
ntohl(ipv4_hdr->daddr),
ntohs(tcp_hdr->source),
ntohs(tcp_hdr->dest));
} else {
process_request(ntohl(ipv4_hdr->saddr),
ntohl(ipv4_hdr->daddr),
ntohs(tcp_hdr->source),
ntohs(tcp_hdr->dest));
}
} else {
dest_port = htons(tcp_hdr->source);
proto = dports2proto.lookup(&dest_port);
if (proto != NULL) {
// clock response receiving time
process_response(ntohl(ipv4_hdr->daddr),
ntohl(ipv4_hdr->saddr),
ntohs(tcp_hdr->dest),
ntohs(tcp_hdr->source));
}
egress_match.dst_ip = ntohl(ipv4_hdr->saddr);
egress_match.dst_port = ntohs(tcp_hdr->source);
policy_ptr = egress_lookup_table.lookup(&egress_match);
if (policy_ptr == NULL) {
egress_match.dst_ip = 0;
policy_ptr = egress_lookup_table.lookup(&egress_match);
}
if (policy_ptr != NULL) {
if (*policy_ptr == RECORD) {
ret = HTTP;
if (tcp_hdr->fin || tcp_hdr->rst) {
process_response(ntohl(ipv4_hdr->daddr),
ntohl(ipv4_hdr->saddr),
ntohs(tcp_hdr->dest),
ntohs(tcp_hdr->source));
}
}
}
}
// everything else drops to TCP
//return ((void*)tcp_hdr);
return ret;
}
static inline app_proto_t egress_tcp_parsing(struct tcphdr *tcp_hdr,
struct iphdr *ipv4_hdr,
void *data_end)
{
unsigned short src_port = htons(tcp_hdr->source);
app_proto_t ret = TCP;
egress_match_t egress_match = {};
policy_action_t *policy_ptr = NULL;
unsigned int *proto = dports2proto.lookup(&src_port);
if (proto != NULL) {
//if (tcp_hdr->fin || tcp_hdr->rst) {
process_response(ntohl(ipv4_hdr->daddr),
ntohl(ipv4_hdr->saddr),
ntohs(tcp_hdr->dest),
ntohs(tcp_hdr->source));
//}
ret = HTTP;
} else {
egress_match.dst_ip = ntohl(ipv4_hdr->daddr);
egress_match.dst_port = ntohs(tcp_hdr->dest);
policy_ptr = egress_lookup_table.lookup(&egress_match);
if (policy_ptr == NULL) {
egress_match.dst_ip = 0;
policy_ptr = egress_lookup_table.lookup(&egress_match);
}
if (policy_ptr != NULL) {
if (*policy_ptr == RECORD) {
process_request(ntohl(ipv4_hdr->saddr),
ntohl(ipv4_hdr->daddr),
ntohs(tcp_hdr->source),
ntohs(tcp_hdr->dest));
ret = HTTP;
}
}
}
//return(ret_hdr);
return ret;
}
static inline int handle_packet(struct __sk_buff *skb, int is_ingress)
{
void *data = (void *)(long)skb->data;
void *data_end = (void *)(long)skb->data_end;
struct eth_hdr *eth = data;
struct iphdr *ipv4_hdr = data + sizeof(*eth);
struct tcphdr *tcp_hdr = data + sizeof(*eth) + sizeof(*ipv4_hdr);
app_proto_t proto = TCP;
/* TODO(s3wong): assuming TCP only for now */
/* single length check */
if (data + sizeof(*eth) + sizeof(*ipv4_hdr) + sizeof(*tcp_hdr) > data_end)
return TC_ACT_OK;
if (eth->h_proto != htons(ETH_P_IP))
return TC_ACT_OK;
// TODO(s3wong): no support for IP options
if (ipv4_hdr->protocol != IPPROTO_TCP || ipv4_hdr->ihl != 5)
return TC_ACT_OK;
if (is_ingress == 1) {
proto = ingress_tcp_parsing(tcp_hdr, ipv4_hdr, data_end);
} else{
proto = egress_tcp_parsing(tcp_hdr, ipv4_hdr, data_end);
}
if (proto == HTTP) {
int offset = is_ingress;
skb_events.perf_submit_skb(skb, skb->len, &offset, sizeof(offset));
}
return TC_ACT_OK;
}
int handle_ingress(struct __sk_buff *skb)
{
return handle_packet(skb, 1);
}
int handle_egress(struct __sk_buff *skb)
{
return handle_packet(skb, 0);
}
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