--- /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>
+#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;
+ }
+}
Code Review / kvmfornfv.git / blobdiff