com32/sysdump/be_tftp.c

   1 /*
   2  * TFTP data output backend
   3  */
   4
   5 #include <string.h>
   6 #include <stdio.h>
   7 #include <syslinux/pxe.h>
   8 #include <syslinux/config.h>
   9 #include <netinet/in.h>
  10 #include <sys/times.h>
  11
  12 #include "backend.h"
  13
  14 enum tftp_opcode {
  15     TFTP_RRQ    = 1,
  16     TFTP_WRQ    = 2,
  17     TFTP_DATA   = 3,
  18     TFTP_ACK    = 4,
  19     TFTP_ERROR  = 5,
  20 };
  21
  22 struct tftp_state {
  23     uint32_t my_ip;
  24     uint32_t srv_ip;
  25     uint32_t srv_gw;
  26     uint16_t my_port;
  27     uint16_t srv_port;
  28     uint16_t seq;
  29 };
  30
  31 #define RCV_BUF 2048
  32
  33 static int send_ack_packet(struct tftp_state *tftp,
  34                            const void *pkt, size_t len)
  35 {
  36     com32sys_t ireg, oreg;
  37     t_PXENV_UDP_WRITE *uw;
  38     t_PXENV_UDP_READ  *ur;
  39     clock_t start;
  40     static const clock_t timeouts[] = {
  41         2, 2, 3, 3, 4, 5, 6, 7, 9, 10, 12, 15, 18, 21, 26, 31,
  42         37, 44, 53, 64, 77, 92, 110, 132, 159, 191, 229, 0
  43     };
  44     const clock_t *timeout;
  45     int err = -1;
  46
  47     uw = lmalloc(sizeof *uw + len);
  48     ur = lmalloc(sizeof *ur + RCV_BUF);
  49
  50     memset(&ireg, 0, sizeof ireg);
  51     ireg.eax.w[0] = 0x0009;
  52
  53     for (timeout = timeouts ; *timeout ; timeout++) {
  54         memset(uw, 0, sizeof uw);
  55         memcpy(uw+1, pkt, len);
  56         uw->ip = tftp->srv_ip;
  57         uw->gw = tftp->srv_gw;
  58         uw->src_port = tftp->my_port;
  59         uw->dst_port = tftp->srv_port ? tftp->srv_port : htons(69);
  60         uw->buffer_size = len;
  61         uw->buffer = FAR_PTR(uw+1);
  62
  63         ireg.ebx.w[0] = PXENV_UDP_WRITE;
  64         ireg.es = SEG(uw);
  65         ireg.edi.w[0] = OFFS(uw);
  66
  67         __intcall(0x22, &ireg, &oreg);
  68
  69         start = times(NULL);
  70
  71         do {
  72             memset(ur, 0, sizeof ur);
  73             ur->src_ip = tftp->srv_ip;
  74             ur->dest_ip = tftp->my_ip;
  75             ur->s_port = tftp->srv_port;
  76             ur->d_port = tftp->my_port;
  77             ur->buffer_size = RCV_BUF;
  78             ur->buffer = FAR_PTR(ur+1);
  79
  80             ireg.ebx.w[0] = PXENV_UDP_READ;
  81             ireg.es = SEG(ur);
  82             ireg.edi.w[0] = OFFS(ur);
  83             __intcall(0x22, &ireg, &oreg);
  84
  85             if (!(oreg.eflags.l & EFLAGS_CF) &&
  86                 ur->status == PXENV_STATUS_SUCCESS &&
  87                 tftp->srv_ip == ur->src_ip &&
  88                 (tftp->srv_port == 0 ||
  89                  tftp->srv_port == ur->s_port)) {
  90                 uint16_t *xb = (uint16_t *)(ur+1);
  91                 if (ntohs(xb[0]) == TFTP_ACK &&
  92                     ntohs(xb[1]) == tftp->seq) {
  93                     tftp->srv_port = ur->s_port;
  94                     err = 0;            /* All good! */
  95                     goto done;
  96                 } else if (ntohs(xb[1]) == TFTP_ERROR) {
  97                     goto done;
  98                 }
  99             }
 100         } while ((clock_t)(times(NULL) - start) < *timeout);
 101     }
 102
 103 done:
 104     lfree(ur);
 105     lfree(uw);
 106
 107     return err;
 108 }
 109
 110 static int be_tftp_write(struct backend *be)
 111 {
 112     static uint16_t local_port = 0x4000;
 113     struct tftp_state tftp;
 114     char buffer[512+4+6];
 115     int nlen;
 116     const union syslinux_derivative_info *sdi =
 117         syslinux_derivative_info();
 118     const char *data = be->outbuf;
 119     size_t len = be->zbytes;
 120     size_t chunk;
 121
 122     tftp.my_ip    = sdi->pxe.myip;
 123     tftp.my_port  = htons(local_port++);
 124     tftp.srv_gw   = ((tftp.srv_ip ^ tftp.my_ip) & sdi->pxe.ipinfo->netmask)
 125         ? sdi->pxe.ipinfo->gateway : 0;
 126     tftp.srv_port = 0;
 127     tftp.seq      = 0;
 128
 129     if (be->argv[1]) {
 130         tftp.srv_ip   = pxe_dns(be->argv[1]);
 131         if (!tftp.srv_ip) {
 132             printf("\nUnable to resolve hostname: %s\n", be->argv[1]);
 133             return -1;
 134         }
 135     } else {
 136         tftp.srv_ip   = sdi->pxe.ipinfo->serverip;
 137         if (!tftp.srv_ip) {
 138             printf("\nNo server IP address\n");
 139             return -1;
 140         }
 141     }
 142
 143     printf("server %u.%u.%u.%u... ",
 144            ((uint8_t *)&tftp.srv_ip)[0],
 145            ((uint8_t *)&tftp.srv_ip)[1],
 146            ((uint8_t *)&tftp.srv_ip)[2],
 147            ((uint8_t *)&tftp.srv_ip)[3]);
 148
 149     buffer[0] = 0;
 150     buffer[1] = TFTP_WRQ;
 151     nlen = strlcpy(buffer+2, be->argv[0], 512);
 152     memcpy(buffer+3+nlen, "octet", 6);
 153
 154     if (send_ack_packet(&tftp, buffer, 2+nlen+1+6))
 155         return -1;
 156
 157     do {
 158         chunk = len >= 512 ? 512 : len;
 159
 160         buffer[1] = TFTP_DATA;
 161         *((uint16_t *)(buffer+2)) = htons(++tftp.seq);
 162         memcpy(buffer+4, data, chunk);
 163         data += chunk;
 164         len -= chunk;
 165
 166         if (send_ack_packet(&tftp, buffer, chunk+4))
 167             return -1;
 168     } while (chunk == 512);
 169
 170     return 0;
 171 }
 172
 173 struct backend be_tftp = {
 174     .name       = "tftp",
 175     .helpmsg    = "filename [tftp_server]",
 176     .minargs    = 1,
 177     .write      = be_tftp_write,
 178 };