diff options
Diffstat (limited to 'qemu/slirp/tftp.c')
| -rw-r--r-- | qemu/slirp/tftp.c | 442 |
1 files changed, 442 insertions, 0 deletions
diff --git a/qemu/slirp/tftp.c b/qemu/slirp/tftp.c new file mode 100644 index 000000000..a329fb281 --- /dev/null +++ b/qemu/slirp/tftp.c @@ -0,0 +1,442 @@ +/* + * tftp.c - a simple, read-only tftp server for qemu + * + * Copyright (c) 2004 Magnus Damm <damm@opensource.se> + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include <slirp.h> +#include "qemu-common.h" + +static inline int tftp_session_in_use(struct tftp_session *spt) +{ + return (spt->slirp != NULL); +} + +static inline void tftp_session_update(struct tftp_session *spt) +{ + spt->timestamp = curtime; +} + +static void tftp_session_terminate(struct tftp_session *spt) +{ + if (spt->fd >= 0) { + close(spt->fd); + spt->fd = -1; + } + g_free(spt->filename); + spt->slirp = NULL; +} + +static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp) +{ + struct tftp_session *spt; + int k; + + for (k = 0; k < TFTP_SESSIONS_MAX; k++) { + spt = &slirp->tftp_sessions[k]; + + if (!tftp_session_in_use(spt)) + goto found; + + /* sessions time out after 5 inactive seconds */ + if ((int)(curtime - spt->timestamp) > 5000) { + tftp_session_terminate(spt); + goto found; + } + } + + return -1; + + found: + memset(spt, 0, sizeof(*spt)); + memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip)); + spt->fd = -1; + spt->client_port = tp->udp.uh_sport; + spt->slirp = slirp; + + tftp_session_update(spt); + + return k; +} + +static int tftp_session_find(Slirp *slirp, struct tftp_t *tp) +{ + struct tftp_session *spt; + int k; + + for (k = 0; k < TFTP_SESSIONS_MAX; k++) { + spt = &slirp->tftp_sessions[k]; + + if (tftp_session_in_use(spt)) { + if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) { + if (spt->client_port == tp->udp.uh_sport) { + return k; + } + } + } + } + + return -1; +} + +static int tftp_read_data(struct tftp_session *spt, uint32_t block_nr, + uint8_t *buf, int len) +{ + int bytes_read = 0; + + if (spt->fd < 0) { + spt->fd = open(spt->filename, O_RDONLY | O_BINARY); + } + + if (spt->fd < 0) { + return -1; + } + + if (len) { + lseek(spt->fd, block_nr * 512, SEEK_SET); + + bytes_read = read(spt->fd, buf, len); + } + + return bytes_read; +} + +static int tftp_send_oack(struct tftp_session *spt, + const char *keys[], uint32_t values[], int nb, + struct tftp_t *recv_tp) +{ + struct sockaddr_in saddr, daddr; + struct mbuf *m; + struct tftp_t *tp; + int i, n = 0; + + m = m_get(spt->slirp); + + if (!m) + return -1; + + memset(m->m_data, 0, m->m_size); + + m->m_data += IF_MAXLINKHDR; + tp = (void *)m->m_data; + m->m_data += sizeof(struct udpiphdr); + + tp->tp_op = htons(TFTP_OACK); + for (i = 0; i < nb; i++) { + n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s", + keys[i]) + 1; + n += snprintf(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u", + values[i]) + 1; + } + + saddr.sin_addr = recv_tp->ip.ip_dst; + saddr.sin_port = recv_tp->udp.uh_dport; + + daddr.sin_addr = spt->client_ip; + daddr.sin_port = spt->client_port; + + m->m_len = sizeof(struct tftp_t) - 514 + n - + sizeof(struct ip) - sizeof(struct udphdr); + udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY); + + return 0; +} + +static void tftp_send_error(struct tftp_session *spt, + uint16_t errorcode, const char *msg, + struct tftp_t *recv_tp) +{ + struct sockaddr_in saddr, daddr; + struct mbuf *m; + struct tftp_t *tp; + + m = m_get(spt->slirp); + + if (!m) { + goto out; + } + + memset(m->m_data, 0, m->m_size); + + m->m_data += IF_MAXLINKHDR; + tp = (void *)m->m_data; + m->m_data += sizeof(struct udpiphdr); + + tp->tp_op = htons(TFTP_ERROR); + tp->x.tp_error.tp_error_code = htons(errorcode); + pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg); + + saddr.sin_addr = recv_tp->ip.ip_dst; + saddr.sin_port = recv_tp->udp.uh_dport; + + daddr.sin_addr = spt->client_ip; + daddr.sin_port = spt->client_port; + + m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) - + sizeof(struct ip) - sizeof(struct udphdr); + + udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY); + +out: + tftp_session_terminate(spt); +} + +static void tftp_send_next_block(struct tftp_session *spt, + struct tftp_t *recv_tp) +{ + struct sockaddr_in saddr, daddr; + struct mbuf *m; + struct tftp_t *tp; + int nobytes; + + m = m_get(spt->slirp); + + if (!m) { + return; + } + + memset(m->m_data, 0, m->m_size); + + m->m_data += IF_MAXLINKHDR; + tp = (void *)m->m_data; + m->m_data += sizeof(struct udpiphdr); + + tp->tp_op = htons(TFTP_DATA); + tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff); + + saddr.sin_addr = recv_tp->ip.ip_dst; + saddr.sin_port = recv_tp->udp.uh_dport; + + daddr.sin_addr = spt->client_ip; + daddr.sin_port = spt->client_port; + + nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf, 512); + + if (nobytes < 0) { + m_free(m); + + /* send "file not found" error back */ + + tftp_send_error(spt, 1, "File not found", tp); + + return; + } + + m->m_len = sizeof(struct tftp_t) - (512 - nobytes) - + sizeof(struct ip) - sizeof(struct udphdr); + + udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY); + + if (nobytes == 512) { + tftp_session_update(spt); + } + else { + tftp_session_terminate(spt); + } + + spt->block_nr++; +} + +static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen) +{ + struct tftp_session *spt; + int s, k; + size_t prefix_len; + char *req_fname; + const char *option_name[2]; + uint32_t option_value[2]; + int nb_options = 0; + + /* check if a session already exists and if so terminate it */ + s = tftp_session_find(slirp, tp); + if (s >= 0) { + tftp_session_terminate(&slirp->tftp_sessions[s]); + } + + s = tftp_session_allocate(slirp, tp); + + if (s < 0) { + return; + } + + spt = &slirp->tftp_sessions[s]; + + /* unspecified prefix means service disabled */ + if (!slirp->tftp_prefix) { + tftp_send_error(spt, 2, "Access violation", tp); + return; + } + + /* skip header fields */ + k = 0; + pktlen -= offsetof(struct tftp_t, x.tp_buf); + + /* prepend tftp_prefix */ + prefix_len = strlen(slirp->tftp_prefix); + spt->filename = g_malloc(prefix_len + TFTP_FILENAME_MAX + 2); + memcpy(spt->filename, slirp->tftp_prefix, prefix_len); + spt->filename[prefix_len] = '/'; + + /* get name */ + req_fname = spt->filename + prefix_len + 1; + + while (1) { + if (k >= TFTP_FILENAME_MAX || k >= pktlen) { + tftp_send_error(spt, 2, "Access violation", tp); + return; + } + req_fname[k] = tp->x.tp_buf[k]; + if (req_fname[k++] == '\0') { + break; + } + } + + /* check mode */ + if ((pktlen - k) < 6) { + tftp_send_error(spt, 2, "Access violation", tp); + return; + } + + if (strcasecmp(&tp->x.tp_buf[k], "octet") != 0) { + tftp_send_error(spt, 4, "Unsupported transfer mode", tp); + return; + } + + k += 6; /* skipping octet */ + + /* do sanity checks on the filename */ + if (!strncmp(req_fname, "../", 3) || + req_fname[strlen(req_fname) - 1] == '/' || + strstr(req_fname, "/../")) { + tftp_send_error(spt, 2, "Access violation", tp); + return; + } + + /* check if the file exists */ + if (tftp_read_data(spt, 0, NULL, 0) < 0) { + tftp_send_error(spt, 1, "File not found", tp); + return; + } + + if (tp->x.tp_buf[pktlen - 1] != 0) { + tftp_send_error(spt, 2, "Access violation", tp); + return; + } + + while (k < pktlen && nb_options < ARRAY_SIZE(option_name)) { + const char *key, *value; + + key = &tp->x.tp_buf[k]; + k += strlen(key) + 1; + + if (k >= pktlen) { + tftp_send_error(spt, 2, "Access violation", tp); + return; + } + + value = &tp->x.tp_buf[k]; + k += strlen(value) + 1; + + if (strcasecmp(key, "tsize") == 0) { + int tsize = atoi(value); + struct stat stat_p; + + if (tsize == 0) { + if (stat(spt->filename, &stat_p) == 0) + tsize = stat_p.st_size; + else { + tftp_send_error(spt, 1, "File not found", tp); + return; + } + } + + option_name[nb_options] = "tsize"; + option_value[nb_options] = tsize; + nb_options++; + } else if (strcasecmp(key, "blksize") == 0) { + int blksize = atoi(value); + + /* If blksize option is bigger than what we will + * emit, accept the option with our packet size. + * Otherwise, simply do as we didn't see the option. + */ + if (blksize >= 512) { + option_name[nb_options] = "blksize"; + option_value[nb_options] = 512; + nb_options++; + } + } + } + + if (nb_options > 0) { + assert(nb_options <= ARRAY_SIZE(option_name)); + tftp_send_oack(spt, option_name, option_value, nb_options, tp); + return; + } + + spt->block_nr = 0; + tftp_send_next_block(spt, tp); +} + +static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen) +{ + int s; + + s = tftp_session_find(slirp, tp); + + if (s < 0) { + return; + } + + tftp_send_next_block(&slirp->tftp_sessions[s], tp); +} + +static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen) +{ + int s; + + s = tftp_session_find(slirp, tp); + + if (s < 0) { + return; + } + + tftp_session_terminate(&slirp->tftp_sessions[s]); +} + +void tftp_input(struct mbuf *m) +{ + struct tftp_t *tp = (struct tftp_t *)m->m_data; + + switch(ntohs(tp->tp_op)) { + case TFTP_RRQ: + tftp_handle_rrq(m->slirp, tp, m->m_len); + break; + + case TFTP_ACK: + tftp_handle_ack(m->slirp, tp, m->m_len); + break; + + case TFTP_ERROR: + tftp_handle_error(m->slirp, tp, m->m_len); + break; + } +} |