Annotation of qemu/slirp/tftp.c, revision 1.1.1.5
1.1 root 1: /*
2: * tftp.c - a simple, read-only tftp server for qemu
1.1.1.2 root 3: *
1.1 root 4: * Copyright (c) 2004 Magnus Damm <damm@opensource.se>
1.1.1.2 root 5: *
1.1 root 6: * Permission is hereby granted, free of charge, to any person obtaining a copy
7: * of this software and associated documentation files (the "Software"), to deal
8: * in the Software without restriction, including without limitation the rights
9: * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10: * copies of the Software, and to permit persons to whom the Software is
11: * furnished to do so, subject to the following conditions:
12: *
13: * The above copyright notice and this permission notice shall be included in
14: * all copies or substantial portions of the Software.
15: *
16: * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17: * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18: * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19: * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20: * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21: * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22: * THE SOFTWARE.
23: */
24:
25: #include <slirp.h>
1.1.1.4 root 26: #include "qemu-common.h"
1.1 root 27:
1.1.1.4 root 28: static inline int tftp_session_in_use(struct tftp_session *spt)
29: {
30: return (spt->slirp != NULL);
31: }
1.1 root 32:
1.1.1.4 root 33: static inline void tftp_session_update(struct tftp_session *spt)
1.1 root 34: {
35: spt->timestamp = curtime;
36: }
37:
38: static void tftp_session_terminate(struct tftp_session *spt)
39: {
1.1.1.4 root 40: qemu_free(spt->filename);
41: spt->slirp = NULL;
1.1 root 42: }
43:
1.1.1.4 root 44: static int tftp_session_allocate(Slirp *slirp, struct tftp_t *tp)
1.1 root 45: {
46: struct tftp_session *spt;
47: int k;
48:
49: for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
1.1.1.4 root 50: spt = &slirp->tftp_sessions[k];
1.1 root 51:
1.1.1.4 root 52: if (!tftp_session_in_use(spt))
1.1 root 53: goto found;
54:
55: /* sessions time out after 5 inactive seconds */
1.1.1.4 root 56: if ((int)(curtime - spt->timestamp) > 5000) {
57: qemu_free(spt->filename);
1.1 root 58: goto found;
1.1.1.4 root 59: }
1.1 root 60: }
61:
62: return -1;
63:
64: found:
65: memset(spt, 0, sizeof(*spt));
66: memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
67: spt->client_port = tp->udp.uh_sport;
1.1.1.4 root 68: spt->slirp = slirp;
1.1 root 69:
70: tftp_session_update(spt);
71:
72: return k;
73: }
74:
1.1.1.4 root 75: static int tftp_session_find(Slirp *slirp, struct tftp_t *tp)
1.1 root 76: {
77: struct tftp_session *spt;
78: int k;
79:
80: for (k = 0; k < TFTP_SESSIONS_MAX; k++) {
1.1.1.4 root 81: spt = &slirp->tftp_sessions[k];
1.1 root 82:
1.1.1.4 root 83: if (tftp_session_in_use(spt)) {
1.1 root 84: if (!memcmp(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip))) {
85: if (spt->client_port == tp->udp.uh_sport) {
86: return k;
87: }
88: }
89: }
90: }
91:
92: return -1;
93: }
94:
95: static int tftp_read_data(struct tftp_session *spt, u_int16_t block_nr,
96: u_int8_t *buf, int len)
97: {
98: int fd;
99: int bytes_read = 0;
100:
1.1.1.4 root 101: fd = open(spt->filename, O_RDONLY | O_BINARY);
1.1 root 102:
103: if (fd < 0) {
104: return -1;
105: }
106:
107: if (len) {
108: lseek(fd, block_nr * 512, SEEK_SET);
109:
110: bytes_read = read(fd, buf, len);
111: }
112:
113: close(fd);
114:
115: return bytes_read;
116: }
117:
1.1.1.2 root 118: static int tftp_send_oack(struct tftp_session *spt,
119: const char *key, uint32_t value,
120: struct tftp_t *recv_tp)
121: {
122: struct sockaddr_in saddr, daddr;
123: struct mbuf *m;
124: struct tftp_t *tp;
125: int n = 0;
126:
1.1.1.4 root 127: m = m_get(spt->slirp);
1.1.1.2 root 128:
129: if (!m)
130: return -1;
131:
132: memset(m->m_data, 0, m->m_size);
133:
134: m->m_data += IF_MAXLINKHDR;
135: tp = (void *)m->m_data;
136: m->m_data += sizeof(struct udpiphdr);
137:
138: tp->tp_op = htons(TFTP_OACK);
1.1.1.3 root 139: n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s",
140: key) + 1;
141: n += snprintf((char *)tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u",
142: value) + 1;
1.1.1.2 root 143:
144: saddr.sin_addr = recv_tp->ip.ip_dst;
145: saddr.sin_port = recv_tp->udp.uh_dport;
146:
147: daddr.sin_addr = spt->client_ip;
148: daddr.sin_port = spt->client_port;
149:
150: m->m_len = sizeof(struct tftp_t) - 514 + n -
151: sizeof(struct ip) - sizeof(struct udphdr);
152: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
153:
154: return 0;
155: }
156:
1.1.1.4 root 157: static void tftp_send_error(struct tftp_session *spt,
158: u_int16_t errorcode, const char *msg,
159: struct tftp_t *recv_tp)
1.1 root 160: {
161: struct sockaddr_in saddr, daddr;
162: struct mbuf *m;
163: struct tftp_t *tp;
164: int nobytes;
165:
1.1.1.4 root 166: m = m_get(spt->slirp);
1.1 root 167:
168: if (!m) {
1.1.1.4 root 169: goto out;
1.1 root 170: }
171:
172: memset(m->m_data, 0, m->m_size);
173:
1.1.1.2 root 174: m->m_data += IF_MAXLINKHDR;
1.1 root 175: tp = (void *)m->m_data;
176: m->m_data += sizeof(struct udpiphdr);
1.1.1.2 root 177:
1.1 root 178: tp->tp_op = htons(TFTP_ERROR);
179: tp->x.tp_error.tp_error_code = htons(errorcode);
1.1.1.3 root 180: pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg), msg);
1.1 root 181:
182: saddr.sin_addr = recv_tp->ip.ip_dst;
183: saddr.sin_port = recv_tp->udp.uh_dport;
184:
185: daddr.sin_addr = spt->client_ip;
186: daddr.sin_port = spt->client_port;
187:
188: nobytes = 2;
189:
1.1.1.2 root 190: m->m_len = sizeof(struct tftp_t) - 514 + 3 + strlen(msg) -
1.1 root 191: sizeof(struct ip) - sizeof(struct udphdr);
192:
193: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
194:
1.1.1.4 root 195: out:
1.1 root 196: tftp_session_terminate(spt);
197: }
198:
1.1.1.2 root 199: static int tftp_send_data(struct tftp_session *spt,
1.1 root 200: u_int16_t block_nr,
201: struct tftp_t *recv_tp)
202: {
203: struct sockaddr_in saddr, daddr;
204: struct mbuf *m;
205: struct tftp_t *tp;
206: int nobytes;
207:
208: if (block_nr < 1) {
209: return -1;
210: }
211:
1.1.1.4 root 212: m = m_get(spt->slirp);
1.1 root 213:
214: if (!m) {
215: return -1;
216: }
217:
218: memset(m->m_data, 0, m->m_size);
219:
1.1.1.2 root 220: m->m_data += IF_MAXLINKHDR;
1.1 root 221: tp = (void *)m->m_data;
222: m->m_data += sizeof(struct udpiphdr);
1.1.1.2 root 223:
1.1 root 224: tp->tp_op = htons(TFTP_DATA);
225: tp->x.tp_data.tp_block_nr = htons(block_nr);
226:
227: saddr.sin_addr = recv_tp->ip.ip_dst;
228: saddr.sin_port = recv_tp->udp.uh_dport;
229:
230: daddr.sin_addr = spt->client_ip;
231: daddr.sin_port = spt->client_port;
232:
233: nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
234:
235: if (nobytes < 0) {
236: m_free(m);
237:
238: /* send "file not found" error back */
239:
240: tftp_send_error(spt, 1, "File not found", tp);
241:
242: return -1;
243: }
244:
1.1.1.2 root 245: m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
1.1 root 246: sizeof(struct ip) - sizeof(struct udphdr);
247:
248: udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
249:
250: if (nobytes == 512) {
251: tftp_session_update(spt);
252: }
253: else {
254: tftp_session_terminate(spt);
255: }
256:
257: return 0;
258: }
259:
1.1.1.4 root 260: static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
1.1 root 261: {
262: struct tftp_session *spt;
1.1.1.4 root 263: int s, k;
264: size_t prefix_len;
265: char *req_fname;
1.1 root 266:
1.1.1.5 ! root 267: /* check if a session already exists and if so terminate it */
! 268: s = tftp_session_find(slirp, tp);
! 269: if (s >= 0) {
! 270: tftp_session_terminate(&slirp->tftp_sessions[s]);
! 271: }
! 272:
1.1.1.4 root 273: s = tftp_session_allocate(slirp, tp);
1.1 root 274:
275: if (s < 0) {
276: return;
277: }
278:
1.1.1.4 root 279: spt = &slirp->tftp_sessions[s];
280:
281: /* unspecifed prefix means service disabled */
282: if (!slirp->tftp_prefix) {
283: tftp_send_error(spt, 2, "Access violation", tp);
284: return;
285: }
1.1 root 286:
1.1.1.4 root 287: /* skip header fields */
288: k = 0;
289: pktlen -= ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);
290:
291: /* prepend tftp_prefix */
292: prefix_len = strlen(slirp->tftp_prefix);
293: spt->filename = qemu_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
294: memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
295: spt->filename[prefix_len] = '/';
1.1 root 296:
297: /* get name */
1.1.1.4 root 298: req_fname = spt->filename + prefix_len + 1;
1.1 root 299:
1.1.1.4 root 300: while (1) {
301: if (k >= TFTP_FILENAME_MAX || k >= pktlen) {
302: tftp_send_error(spt, 2, "Access violation", tp);
1.1 root 303: return;
304: }
1.1.1.4 root 305: req_fname[k] = (char)tp->x.tp_buf[k];
306: if (req_fname[k++] == '\0') {
1.1 root 307: break;
308: }
309: }
1.1.1.2 root 310:
1.1 root 311: /* check mode */
1.1.1.4 root 312: if ((pktlen - k) < 6) {
313: tftp_send_error(spt, 2, "Access violation", tp);
1.1 root 314: return;
315: }
1.1.1.2 root 316:
1.1.1.4 root 317: if (memcmp(&tp->x.tp_buf[k], "octet\0", 6) != 0) {
1.1 root 318: tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
319: return;
320: }
321:
1.1.1.2 root 322: k += 6; /* skipping octet */
323:
1.1 root 324: /* do sanity checks on the filename */
1.1.1.4 root 325: if (!strncmp(req_fname, "../", 3) ||
326: req_fname[strlen(req_fname) - 1] == '/' ||
327: strstr(req_fname, "/../")) {
1.1 root 328: tftp_send_error(spt, 2, "Access violation", tp);
329: return;
330: }
331:
332: /* check if the file exists */
1.1.1.4 root 333: if (tftp_read_data(spt, 0, NULL, 0) < 0) {
1.1 root 334: tftp_send_error(spt, 1, "File not found", tp);
335: return;
336: }
337:
1.1.1.4 root 338: if (tp->x.tp_buf[pktlen - 1] != 0) {
1.1.1.2 root 339: tftp_send_error(spt, 2, "Access violation", tp);
340: return;
341: }
342:
1.1.1.4 root 343: while (k < pktlen) {
1.1.1.2 root 344: const char *key, *value;
345:
1.1.1.4 root 346: key = (const char *)&tp->x.tp_buf[k];
1.1.1.2 root 347: k += strlen(key) + 1;
348:
1.1.1.4 root 349: if (k >= pktlen) {
1.1.1.2 root 350: tftp_send_error(spt, 2, "Access violation", tp);
351: return;
352: }
353:
1.1.1.4 root 354: value = (const char *)&tp->x.tp_buf[k];
1.1.1.2 root 355: k += strlen(value) + 1;
356:
357: if (strcmp(key, "tsize") == 0) {
358: int tsize = atoi(value);
359: struct stat stat_p;
360:
1.1.1.4 root 361: if (tsize == 0) {
362: if (stat(spt->filename, &stat_p) == 0)
1.1.1.2 root 363: tsize = stat_p.st_size;
364: else {
365: tftp_send_error(spt, 1, "File not found", tp);
366: return;
367: }
368: }
369:
370: tftp_send_oack(spt, "tsize", tsize, tp);
1.1.1.5 ! root 371: return;
1.1.1.2 root 372: }
373: }
374:
1.1 root 375: tftp_send_data(spt, 1, tp);
376: }
377:
1.1.1.4 root 378: static void tftp_handle_ack(Slirp *slirp, struct tftp_t *tp, int pktlen)
1.1 root 379: {
380: int s;
381:
1.1.1.4 root 382: s = tftp_session_find(slirp, tp);
1.1 root 383:
384: if (s < 0) {
385: return;
386: }
387:
1.1.1.4 root 388: if (tftp_send_data(&slirp->tftp_sessions[s],
1.1.1.2 root 389: ntohs(tp->x.tp_data.tp_block_nr) + 1,
1.1 root 390: tp) < 0) {
391: return;
392: }
393: }
394:
1.1.1.5 ! root 395: static void tftp_handle_error(Slirp *slirp, struct tftp_t *tp, int pktlen)
! 396: {
! 397: int s;
! 398:
! 399: s = tftp_session_find(slirp, tp);
! 400:
! 401: if (s < 0) {
! 402: return;
! 403: }
! 404:
! 405: tftp_session_terminate(&slirp->tftp_sessions[s]);
! 406: }
! 407:
1.1 root 408: void tftp_input(struct mbuf *m)
409: {
410: struct tftp_t *tp = (struct tftp_t *)m->m_data;
411:
412: switch(ntohs(tp->tp_op)) {
413: case TFTP_RRQ:
1.1.1.4 root 414: tftp_handle_rrq(m->slirp, tp, m->m_len);
1.1 root 415: break;
416:
417: case TFTP_ACK:
1.1.1.4 root 418: tftp_handle_ack(m->slirp, tp, m->m_len);
1.1 root 419: break;
1.1.1.5 ! root 420:
! 421: case TFTP_ERROR:
! 422: tftp_handle_error(m->slirp, tp, m->m_len);
! 423: break;
1.1 root 424: }
425: }
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