diff options
Diffstat (limited to 'slirp-android/tftp.c')
-rw-r--r-- | slirp-android/tftp.c | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/slirp-android/tftp.c b/slirp-android/tftp.c new file mode 100644 index 0000000..307610b --- /dev/null +++ b/slirp-android/tftp.c @@ -0,0 +1,431 @@ +/* + * 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; + } +} |