--- /dev/null
+/*
+ * 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>
+
+struct tftp_session {
+ int in_use;
+ unsigned char filename[TFTP_FILENAME_MAX];
+
+ struct in_addr client_ip;
+ u_int16_t client_port;
+
+ struct timeval timestamp;
+};
+
+struct tftp_session tftp_sessions[TFTP_SESSIONS_MAX];
+
+char *tftp_prefix;
+
+static void tftp_session_update(struct tftp_session *spt)
+{
+ gettimeofday(&spt->timestamp, 0);
+ 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;
+ struct timeval tv;
+ int k;
+
+ gettimeofday(&tv, 0);
+
+ 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 (tv.tv_sec > (spt->timestamp.tv_sec + 5)) {
+ goto found;
+ }
+ }
+
+ return -1;
+
+ found:
+ memset(spt, 0, sizeof(*spt));
+ memcpy(&spt->client_ip, &tp->ip.ip_src, sizeof(spt->client_ip));
+ spt->client_port = 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 (!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, u_int16_t block_nr,
+ u_int8_t *buf, int len)
+{
+ int fd;
+ int bytes_read = 0;
+
+ fd = open(spt->filename, O_RDONLY);
+
+ 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_error(struct tftp_session *spt,
+ u_int16_t errorcode, const char *msg,
+ struct tftp_t *recv_tp)
+{
+ struct sockaddr_in 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);
+ strcpy(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;
+
+ 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)
+{
+ struct sockaddr_in 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);
+
+ 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, 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;
+ }
+
+ /* do sanity checks on the filename */
+
+ if ((spt->filename[0] != '/')
+ || (spt->filename[strlen(spt->filename) - 1] == '/')
+ || strstr(spt->filename, "/../")) {
+ tftp_send_error(spt, 2, "Access violation", tp);
+ return;
+ }
+
+ /* only allow exported prefixes */
+
+ if (!tftp_prefix
+ || (strncmp(spt->filename, tftp_prefix, strlen(tftp_prefix)) != 0)) {
+ 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;
+ }
+
+ 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;
+ }
+}
projects / qemu / commitdiff