/external/qemu/slirp-android/tftp.c
C | 431 lines | 293 code | 108 blank | 30 comment | 51 complexity | 941c47eeb4a64515734d3554fb99e127 MD5 | raw file
- /*
- * 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" // for pstrcpy
- struct tftp_session {
- int in_use;
- unsigned char filename[TFTP_FILENAME_MAX];
- uint32_t client_ip;
- uint16_t client_port;
- int timestamp;
- };
- static struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];
- const char *tftp_prefix;
- static void tftp_session_update(struct tftp_session *spt)
- {
- spt->timestamp = curtime;
- spt->in_use = 1;
- }
- static void tftp_session_terminate(struct tftp_session *spt)
- {
- spt->in_use = 0;
- }
- static int tftp_session_allocate(struct tftp_t *tp)
- {
- struct tftp_session *spt;
- int k;
- for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
- spt = &tftp_sessions[k];
- if (!spt->in_use)
- goto found;
- /* sessions time out after 5 inactive seconds */
- if ((int)(curtime - spt->timestamp) > 5000)
- goto found;
- }
- return -1;
- found:
- memset(spt, 0, sizeof(*spt));
- spt->client_ip = ip_geth(tp->ip.ip_src);
- spt->client_port = port_geth(tp->udp.uh_sport);
- tftp_session_update(spt);
- return k;
- }
- static int tftp_session_find(struct tftp_t *tp)
- {
- struct tftp_session *spt;
- int k;
- for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
- spt = &tftp_sessions[k];
- if (spt->in_use) {
- if (spt->client_ip == ip_geth(tp->ip.ip_src)) {
- if (spt->client_port == port_geth(tp->udp.uh_sport)) {
- return k;
- }
- }
- }
- }
- return -1;
- }
- static int tftp_read_data(struct tftp_session *spt, u_int16_t block_nr,
- u_int8_t *buf, int len)
- {
- int fd;
- int bytes_read = 0;
- char buffer[1024];
- int n;
- n = snprintf(buffer, sizeof(buffer), "%s/%s",
- tftp_prefix, spt->filename);
- if (n >= sizeof(buffer))
- return -1;
- fd = open(buffer, O_RDONLY | O_BINARY);
- if (fd < 0) {
- return -1;
- }
- if (len) {
- lseek(fd, block_nr * 512, SEEK_SET);
- bytes_read = read(fd, buf, len);
- }
- close(fd);
- return bytes_read;
- }
- static int tftp_send_oack(struct tftp_session *spt,
- const char *key, uint32_t value,
- struct tftp_t *recv_tp)
- {
- SockAddress saddr, daddr;
- struct mbuf *m;
- struct tftp_t *tp;
- int n = 0;
- m = m_get();
- 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);
- n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
- key) + 1;
- n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
- value) + 1;
- sock_address_init_inet( &saddr,
- ip_geth(recv_tp->ip.ip_dst),
- port_geth(recv_tp->udp.uh_dport) );
- sock_address_init_inet( &daddr,
- spt->client_ip,
- 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 int tftp_send_error(struct tftp_session *spt,
- u_int16_t errorcode, const char *msg,
- struct tftp_t *recv_tp)
- {
- SockAddress saddr, daddr;
- struct mbuf *m;
- struct tftp_t *tp;
- int nobytes;
- m = m_get();
- 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_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);
- sock_address_init_inet( &saddr,
- ip_geth(recv_tp->ip.ip_dst),
- port_geth(recv_tp->udp.uh_dport) );
- sock_address_init_inet( &daddr,
- spt->client_ip,
- spt->client_port );
- nobytes = 2;
- 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);
- tftp_session_terminate(spt);
- return 0;
- }
- static int tftp_send_data(struct tftp_session *spt,
- u_int16_t block_nr,
- struct tftp_t *recv_tp)
- {
- SockAddress saddr, daddr;
- struct mbuf *m;
- struct tftp_t *tp;
- int nobytes;
- if (block_nr < 1) {
- return -1;
- }
- m = m_get();
- 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_DATA);
- tp->x.tp_data.tp_block_nr = htons(block_nr);
- sock_address_init_inet( &saddr,
- ip_geth(recv_tp->ip.ip_dst),
- port_geth(recv_tp->udp.uh_dport) );
- sock_address_init_inet( &daddr,
- spt->client_ip,
- spt->client_port );
- nobytes = tftp_read_data(spt, block_nr - 1, 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 -1;
- }
- 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);
- }
- return 0;
- }
- static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
- {
- struct tftp_session *spt;
- int s, k, n;
- u_int8_t *src, *dst;
- s = tftp_session_allocate(tp);
- if (s < 0) {
- return;
- }
- spt = &tftp_sessions[s];
- src = tp->x.tp_buf;
- dst = spt->filename;
- n = pktlen - ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);
- /* get name */
- for (k = 0; k < n; k++) {
- if (k < TFTP_FILENAME_MAX) {
- dst[k] = src[k];
- }
- else {
- return;
- }
- if (src[k] == '\0') {
- break;
- }
- }
- if (k >= n) {
- return;
- }
- k++;
- /* check mode */
- if ((n - k) < 6) {
- return;
- }
- if (memcmp(&src[k], "octet\0", 6) != 0) {
- tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
- return;
- }
- k += 6; /* skipping octet */
- /* do sanity checks on the filename */
- if ((spt->filename[0] != '/')
- || (spt->filename[strlen((char *)spt->filename) - 1] == '/')
- || strstr((char *)spt->filename, "/../")) {
- tftp_send_error(spt, 2, "Access violation", tp);
- return;
- }
- /* only allow exported prefixes */
- if (!tftp_prefix) {
- tftp_send_error(spt, 2, "Access violation", tp);
- return;
- }
- /* check if the file exists */
- if (tftp_read_data(spt, 0, spt->filename, 0) < 0) {
- tftp_send_error(spt, 1, "File not found", tp);
- return;
- }
- if (src[n - 1] != 0) {
- tftp_send_error(spt, 2, "Access violation", tp);
- return;
- }
- while (k < n) {
- const char *key, *value;
- key = (char *)src + k;
- k += strlen(key) + 1;
- if (k >= n) {
- tftp_send_error(spt, 2, "Access violation", tp);
- return;
- }
- value = (char *)src + k;
- k += strlen(value) + 1;
- if (strcmp(key, "tsize") == 0) {
- int tsize = atoi(value);
- struct stat stat_p;
- if (tsize == 0 && tftp_prefix) {
- char buffer[1024];
- int len;
- len = snprintf(buffer, sizeof(buffer), "%s/%s",
- tftp_prefix, spt->filename);
- if (stat(buffer, &stat_p) == 0)
- tsize = stat_p.st_size;
- else {
- tftp_send_error(spt, 1, "File not found", tp);
- return;
- }
- }
- tftp_send_oack(spt, "tsize", tsize, tp);
- }
- }
- tftp_send_data(spt, 1, tp);
- }
- static void tftp_handle_ack(struct tftp_t *tp, int pktlen)
- {
- int s;
- s = tftp_session_find(tp);
- if (s < 0) {
- return;
- }
- if (tftp_send_data(&tftp_sessions[s],
- ntohs(tp->x.tp_data.tp_block_nr) + 1,
- tp) < 0) {
- return;
- }
- }
- 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(tp, m->m_len);
- break;
- case TFTP_ACK:
- tftp_handle_ack(tp, m->m_len);
- break;
- }
- }