nmrp.c

   1 /**
   2  * nmrpflash - Netgear Unbrick Utility
   3  * Copyright (C) 2016 Joseph Lehner <joseph.c.lehner@gmail.com>
   4  *
   5  * nmrpflash is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * nmrpflash is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with nmrpflash.  If not, see <http://www.gnu.org/licenses/>.
  17  *
  18  */
  19
  20 #include <signal.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <errno.h>
  25 #include <stdio.h>
  26 #include <time.h>
  27 #include "nmrpd.h"
  28
  29 #define NMRP_HDR_LEN 6
  30 #define NMRP_OPT_HDR_LEN 4
  31 #define NMRP_MIN_PKT_LEN (sizeof(struct eth_hdr) +  NMRP_HDR_LEN)
  32
  33 #define NMRP_MAX_OPT_SIZE 12
  34 #define NMRP_MAX_OPT_NUM 3
  35
  36 #define NMRP_OPT_NEXT(x) ((struct nmrp_opt*)(((char*)x) + x->len))
  37
  38 #define ETH_P_NMRP 0x0912
  39 #define IP_LEN 4
  40 #define MAX_LOOP_RECV 1024
  41
  42 #ifndef PACKED
  43 #define PACKED __attribute__((__packed__))
  44 #endif
  45
  46 #ifdef NMRPFLASH_WINDOWS
  47 #define setenv(name, value, overwrite) SetEnvironmentVariable(name, value)
  48 #endif
  49
  50 enum nmrp_code {
  51         NMRP_C_NONE = 0,
  52         NMRP_C_ADVERTISE = 1,
  53         NMRP_C_CONF_REQ = 2,
  54         NMRP_C_CONF_ACK = 3,
  55         NMRP_C_CLOSE_REQ = 4,
  56         NMRP_C_CLOSE_ACK = 5,
  57         NMRP_C_KEEP_ALIVE_REQ = 6,
  58         NMRP_C_KEEP_ALIVE_ACK = 7,
  59         NMRP_C_TFTP_UL_REQ = 16
  60 };
  61
  62 enum nmrp_opt_type {
  63         NMRP_O_MAGIC_NO = 0x0001,
  64         NMRP_O_DEV_IP = 0x0002,
  65         NMRP_O_DEV_REGION = 0x0004,
  66         NMRP_O_FW_UP = 0x0101,
  67         NMRP_O_ST_UP = 0x0102,
  68         NMRP_O_FILE_NAME = 0x0181
  69 };
  70
  71 struct nmrp_opt {
  72         uint16_t type;
  73         uint16_t len;
  74         union {
  75                 uint8_t magic[4];
  76                 uint16_t region;
  77                 struct {
  78                         uint8_t addr[4];
  79                         uint8_t mask[4];
  80                 } ip;
  81         } val;
  82 } PACKED;
  83
  84 struct nmrp_msg {
  85         uint16_t reserved;
  86         uint8_t code;
  87         uint8_t id;
  88         uint16_t len;
  89         /* only opts[0] is valid! think of this as a char* */
  90         struct nmrp_opt opts[NMRP_MAX_OPT_NUM];
  91         /* this is NOT part of the transmitted packet */
  92         uint32_t num_opts;
  93 } PACKED;
  94
  95 struct nmrp_pkt {
  96         struct eth_hdr eh;
  97         struct nmrp_msg msg;
  98 } PACKED;
  99
 100 static const char *msg_code_str(uint16_t code)
 101 {
 102 #define CASE_CODE(x) case NMRP_C_ ## x: return #x
 103         static char buf[16];
 104
 105         switch (code) {
 106                 CASE_CODE(ADVERTISE);
 107                 CASE_CODE(CONF_REQ);
 108                 CASE_CODE(CONF_ACK);
 109                 CASE_CODE(CLOSE_REQ);
 110                 CASE_CODE(CLOSE_ACK);
 111                 CASE_CODE(KEEP_ALIVE_REQ);
 112                 CASE_CODE(KEEP_ALIVE_ACK);
 113                 CASE_CODE(TFTP_UL_REQ);
 114                 default:
 115                         snprintf(buf, sizeof(buf), "%04x", code);
 116                         return buf;
 117         }
 118 #undef CASE_CODE
 119 }
 120
 121 static uint16_t to_region_code(const char *region)
 122 {
 123 #define REGION_CODE(r, c) if (!strcasecmp(region, r)) return c
 124         REGION_CODE("NA", 0x0001);
 125         REGION_CODE("WW", 0x0002);
 126         REGION_CODE("GR", 0x0003);
 127         REGION_CODE("PR", 0x0004);
 128         REGION_CODE("RU", 0x0005);
 129         REGION_CODE("BZ", 0x0006);
 130         REGION_CODE("IN", 0x0007);
 131         REGION_CODE("KO", 0x0008);
 132         REGION_CODE("JP", 0x0009);
 133 #undef REGION_CODE
 134         return 0;
 135 }
 136
 137 static void msg_dump(struct nmrp_msg *msg, int dump_opts)
 138 {
 139         struct nmrp_opt *opt;
 140         int remain_len, len, i;
 141
 142         fprintf(stderr, "res=0x%04x, code=0x%02x, id=0x%02x, len=%u",
 143                         msg->reserved, msg->code, msg->id, msg->len);
 144
 145         remain_len = msg->len - NMRP_HDR_LEN;
 146         fprintf(stderr, "%s\n", remain_len ? "" : " (no opts)");
 147
 148         if (dump_opts) {
 149                 opt = msg->opts;
 150
 151                 while (remain_len > 0) {
 152                         len = opt->len;
 153                         fprintf(stderr, "  opt type=%u, len=%u", opt->type, len);
 154                         if (len) {
 155                                 for (i = 0; i != len - NMRP_OPT_HDR_LEN; ++i) {
 156                                         if (!(i % 16)) {
 157                                                 fprintf(stderr, "\n  ");
 158                                         }
 159
 160                                         fprintf(stderr, "%02x ", ((char*)&opt->val)[i] & 0xff);
 161                                 }
 162                                 fprintf(stderr, "\n");
 163                         }
 164                         remain_len -= len;
 165                         opt = NMRP_OPT_NEXT(opt);
 166                 }
 167         }
 168 }
 169
 170 static void msg_hton(struct nmrp_msg *msg)
 171 {
 172         uint32_t i = 0;
 173         struct nmrp_opt *opt = msg->opts, *next;
 174
 175         msg->reserved = htons(msg->reserved);
 176         msg->len = htons(msg->len);
 177
 178         for (; i != msg->num_opts; ++i) {
 179                 next = NMRP_OPT_NEXT(opt);
 180                 opt->len = htons(opt->len);
 181                 opt->type = htons(opt->type);
 182                 opt = next;
 183         }
 184 }
 185
 186 static void msg_hdr_ntoh(struct nmrp_msg *msg)
 187 {
 188         msg->reserved = ntohs(msg->reserved);
 189         msg->len = ntohs(msg->len);
 190 }
 191
 192 static int msg_ntoh(struct nmrp_msg *msg)
 193 {
 194         struct nmrp_opt *opt = msg->opts;
 195         int remaining;
 196
 197         remaining = msg->len - NMRP_HDR_LEN;
 198
 199         // FIXME maximum of two options supported, maximum option
 200         // size is 12
 201         if (remaining < NMRP_MAX_OPT_NUM * NMRP_MAX_OPT_SIZE) {
 202                 while (remaining > 0) {
 203                         if (remaining < NMRP_OPT_HDR_LEN) {
 204                                 break;
 205                         }
 206
 207                         opt->type = ntohs(opt->type);
 208                         opt->len = ntohs(opt->len);
 209
 210                         if (opt->len > NMRP_MAX_OPT_SIZE) {
 211                                 break;
 212                         }
 213
 214                         remaining -= opt->len;
 215                         opt = NMRP_OPT_NEXT(opt);
 216                 }
 217
 218                 if (!remaining) {
 219                         return 0;
 220                 }
 221         }
 222
 223         fprintf(stderr, "Unexpected message format.\n");
 224         msg_dump(msg, 0);
 225         return 1;
 226 }
 227
 228 static void *msg_opt_data(struct nmrp_msg *msg, uint16_t type, uint16_t *len)
 229 {
 230         static char buf[128];
 231         struct nmrp_opt *opt = msg->opts;
 232         int remaining = msg->len - NMRP_HDR_LEN;
 233
 234         memset(buf, 0, sizeof(buf));
 235
 236         while (remaining > 0) {
 237                 if (opt->type == type) {
 238                         if (opt->len == NMRP_OPT_HDR_LEN) {
 239                                 return NULL;
 240                         }
 241                         *len = opt->len - NMRP_OPT_HDR_LEN;
 242                         memcpy(buf, &opt->val, MIN(*len, sizeof(buf)-1));
 243                         return buf;
 244                 }
 245
 246                 remaining -= opt->len;
 247                 opt = NMRP_OPT_NEXT(opt);
 248         }
 249
 250         return NULL;
 251 }
 252
 253 static void msg_opt_add(struct nmrp_msg *msg, uint16_t type, void *data,
 254                 uint16_t len)
 255 {
 256         uint32_t i = 0;
 257         struct nmrp_opt *opt = msg->opts;
 258
 259         if (len + NMRP_OPT_HDR_LEN > NMRP_MAX_OPT_SIZE
 260                         || msg->num_opts == NMRP_MAX_OPT_NUM) {
 261                 fprintf(stderr, "Invalid option - this is a bug.\n");
 262         }
 263
 264         for (; i <= msg->num_opts; ++i) {
 265                 opt = NMRP_OPT_NEXT(opt);
 266         }
 267
 268         opt->len = NMRP_OPT_HDR_LEN + len;
 269         opt->type = type;
 270
 271         if (len) {
 272                 memcpy(&opt->val, data, len);
 273         }
 274
 275         msg->len += opt->len;
 276         ++msg->num_opts;
 277 }
 278
 279 static inline void msg_init(struct nmrp_msg *msg, uint16_t code)
 280 {
 281         memset(msg, 0, sizeof(*msg));
 282         msg->len = NMRP_HDR_LEN;
 283         msg->code = code;
 284 }
 285
 286 static int pkt_send(struct ethsock *sock, struct nmrp_pkt *pkt)
 287 {
 288         size_t len = ntohs(pkt->msg.len) + sizeof(pkt->eh);
 289         return ethsock_send(sock, pkt, len);
 290 }
 291
 292 static int pkt_recv(struct ethsock *sock, struct nmrp_pkt *pkt)
 293 {
 294         ssize_t bytes, len;
 295
 296         memset(pkt, 0, sizeof(*pkt));
 297         bytes = ethsock_recv(sock, pkt, sizeof(*pkt));
 298         if (bytes < 0) {
 299                 return 1;
 300         } else if (!bytes) {
 301                 return 2;
 302         } else if (bytes < NMRP_MIN_PKT_LEN) {
 303                 fprintf(stderr, "Short packet (%d bytes)\n", (int)bytes);
 304                 return 1;
 305         }
 306
 307         msg_hdr_ntoh(&pkt->msg);
 308         len = pkt->msg.len + sizeof(pkt->eh);
 309
 310         if (bytes < len) {
 311                 fprintf(stderr, "Short packet (expected %d, got %d).\n",
 312                                 (int)len, (int)bytes);
 313                 return 1;
 314         }
 315
 316         return msg_ntoh(&pkt->msg);
 317 }
 318
 319 static int mac_parse(const char *str, uint8_t *hwaddr)
 320 {
 321         int i;
 322         unsigned data[6];
 323
 324         sscanf(str, "%02x:%02x:%02x:%02x:%02x:%02x%n",
 325                         data, data + 1, data + 2, data + 3, data + 4, data + 5, &i);
 326
 327         if (i == strlen(str)) {
 328                 for (i = 0; i != 6; ++i) {
 329                         if (data[i] > 255) {
 330                                 break;
 331                         }
 332
 333                         hwaddr[i] = data[i] & 0xff;
 334                 }
 335
 336                 if (i == 6) {
 337                         return 1;
 338                 }
 339         }
 340         return 0;
 341 }
 342
 343 struct is_valid_ip_arg
 344 {
 345         struct in_addr *ipaddr;
 346         struct in_addr *ipmask;
 347         int result;
 348 };
 349
 350 static int is_valid_ip_cb(struct ethsock_ip_callback_args *args)
 351 {
 352 #define SUBNET(x) ((x)->ipaddr->s_addr & (x)->ipmask->s_addr)
 353         struct is_valid_ip_arg *arg = args->arg;
 354         if (SUBNET(args) == SUBNET(arg)) {
 355                 arg->result = args->ipaddr->s_addr != arg->ipaddr->s_addr;
 356                 return 0;
 357         }
 358
 359         return 1;
 360 #undef SUBNET
 361 }
 362
 363 static int is_valid_ip(struct ethsock *sock, struct in_addr *ipaddr,
 364                 struct in_addr *ipmask)
 365 {
 366         int status;
 367         struct is_valid_ip_arg arg = {
 368                 .ipaddr = ipaddr,
 369                 .ipmask = ipmask,
 370                 .result = 0
 371         };
 372
 373         status = ethsock_for_each_ip(sock, is_valid_ip_cb, &arg);
 374         return status < 0 ? status : arg.result;
 375 }
 376
 377 static struct ethsock *gsock = NULL;
 378 static struct ethsock_ip_undo *gundo = NULL;
 379 static int garp = 0;
 380 static struct in_addr arpip = { 0 };
 381 static uint8_t arpmac[6] = { 0 };
 382
 383 static void sigh(int sig)
 384 {
 385         printf("\n");
 386         if (gsock) {
 387                 if (garp) {
 388                         ethsock_arp_del(gsock, arpmac, &arpip);
 389                 }
 390                 ethsock_ip_del(gsock, &gundo);
 391                 ethsock_close(gsock);
 392                 gsock = NULL;
 393         }
 394
 395         exit(1);
 396 }
 397
 398 static const char *spinner = "\\|/-";
 399
 400 int nmrp_do(struct nmrpd_args *args)
 401 {
 402         struct nmrp_pkt tx, rx;
 403         uint8_t *src, dest[6];
 404         uint16_t len, region;
 405         char *filename;
 406         time_t beg;
 407         int i, status, ulreqs, expect, upload_ok, autoip;
 408         struct ethsock *sock;
 409         uint32_t intf_addr;
 410         void (*sigh_orig)(int);
 411         struct {
 412                 struct in_addr addr;
 413                 struct in_addr mask;
 414         } PACKED ipconf;
 415
 416         if (args->op != NMRP_UPLOAD_FW) {
 417                 fprintf(stderr, "Operation not implemented.\n");
 418                 return 1;
 419         }
 420
 421         if (!mac_parse(args->mac, dest)) {
 422                 fprintf(stderr, "Invalid MAC address '%s'.\n", args->mac);
 423                 return 1;
 424         }
 425
 426         if ((ipconf.mask.s_addr = inet_addr(args->ipmask)) == INADDR_NONE) {
 427                 fprintf(stderr, "Invalid subnet mask '%s'.\n", args->ipmask);
 428                 return 1;
 429         }
 430
 431         if (!args->ipaddr) {
 432                 autoip = true;
 433                 args->ipaddr = "10.11.12.252";
 434
 435                 if (!args->ipaddr_intf) {
 436                         args->ipaddr_intf = "10.11.12.253";
 437                 }
 438         } else if (args->ipaddr_intf) {
 439                 autoip = true;
 440         } else {
 441                 autoip = false;
 442         }
 443
 444         if ((ipconf.addr.s_addr = inet_addr(args->ipaddr)) == INADDR_NONE) {
 445                 fprintf(stderr, "Invalid IP address '%s'.\n", args->ipaddr);
 446                 return 1;
 447         }
 448
 449         if (args->ipaddr_intf && (intf_addr = inet_addr(args->ipaddr_intf)) == INADDR_NONE) {
 450                 fprintf(stderr, "Invalid IP address '%s'.\n", args->ipaddr_intf);
 451                 return 1;
 452         }
 453
 454         if (args->file_local && strcmp(args->file_local, "-") && access(args->file_local, R_OK) == -1) {
 455                 fprintf(stderr, "Error accessing file '%s'.\n", args->file_local);
 456                 return 1;
 457         }
 458
 459         if (args->file_remote) {
 460                 if (!tftp_is_valid_filename(args->file_remote)) {
 461                         fprintf(stderr, "Invalid remote filename '%s'.\n",
 462                                         args->file_remote);
 463                         return 1;
 464                 }
 465         }
 466
 467         if (args->region) {
 468                 region = htons(to_region_code(args->region));
 469                 if (!region) {
 470                         fprintf(stderr, "Invalid region code '%s'.\n", args->region);
 471                         return 1;
 472                 }
 473         } else {
 474                 region = 0;
 475         }
 476
 477         status = 1;
 478
 479         sock = ethsock_create(args->intf, ETH_P_NMRP);
 480         if (!sock) {
 481                 return 1;
 482         }
 483
 484         gsock = sock;
 485         garp = 0;
 486         sigh_orig = signal(SIGINT, sigh);
 487
 488         if (!autoip) {
 489                 status = is_valid_ip(sock, &ipconf.addr, &ipconf.mask);
 490                 if (status <= 0) {
 491                         if (!status) {
 492                                 fprintf(stderr, "Address %s/%s cannot be used on interface %s.\n",
 493                                                 args->ipaddr, args->ipmask, args->intf);
 494                         }
 495                         goto out;
 496                 }
 497         } else {
 498                 if (verbosity) {
 499                         printf("Adding %s to interface %s.\n", args->ipaddr_intf, args->intf);
 500                 }
 501
 502                 if (ethsock_ip_add(sock, intf_addr, ipconf.mask.s_addr, &gundo) != 0) {
 503                         goto out;
 504                 }
 505         }
 506
 507         if (ethsock_set_timeout(sock, args->rx_timeout)) {
 508                 goto out;
 509         }
 510
 511         src = ethsock_get_hwaddr(sock);
 512         if (!src) {
 513                 goto out;
 514         }
 515
 516         memcpy(tx.eh.ether_shost, src, 6);
 517         memcpy(tx.eh.ether_dhost, dest, 6);
 518         tx.eh.ether_type = htons(ETH_P_NMRP);
 519
 520         msg_init(&tx.msg, NMRP_C_ADVERTISE);
 521         msg_opt_add(&tx.msg, NMRP_O_MAGIC_NO, "NTGR", 4);
 522         msg_hton(&tx.msg);
 523
 524         i = 0;
 525         upload_ok = 0;
 526         beg = time(NULL);
 527
 528         while (1) {
 529                 printf("\rAdvertising NMRP server on %s ... %c",
 530                                 args->intf, spinner[i]);
 531                 fflush(stdout);
 532                 i = (i + 1) & 3;
 533
 534                 if (pkt_send(sock, &tx) < 0) {
 535                         perror("sendto");
 536                         goto out;
 537                 }
 538
 539                 status = pkt_recv(sock, &rx);
 540                 if (status == 0 && memcmp(rx.eh.ether_dhost, src, 6) == 0) {
 541                         break;
 542                 } else if (status == 1) {
 543                         goto out;
 544                 } else {
 545                         if ((time(NULL) - beg) >= 60) {
 546                                 printf("\nNo response after 60 seconds. Bailing out.\n");
 547                                 goto out;
 548                         }
 549                 }
 550         }
 551
 552         printf("\n");
 553
 554         expect = NMRP_C_CONF_REQ;
 555         ulreqs = 0;
 556
 557         do {
 558                 if (expect != NMRP_C_NONE && rx.msg.code != expect) {
 559                         fprintf(stderr, "Received %s while waiting for %s!\n",
 560                                         msg_code_str(rx.msg.code), msg_code_str(expect));
 561                 }
 562
 563                 msg_init(&tx.msg, NMRP_C_NONE);
 564
 565                 status = 1;
 566
 567                 switch (rx.msg.code) {
 568                         case NMRP_C_ADVERTISE:
 569                                 printf("Received NMRP advertisement from %s.\n",
 570                                                 mac_to_str(rx.eh.ether_shost));
 571                                 status = 1;
 572                                 goto out;
 573                         case NMRP_C_CONF_REQ:
 574                                 tx.msg.code = NMRP_C_CONF_ACK;
 575
 576                                 msg_opt_add(&tx.msg, NMRP_O_DEV_IP, &ipconf, 8);
 577                                 msg_opt_add(&tx.msg, NMRP_O_FW_UP, NULL, 0);
 578
 579 #ifdef NMRPFLASH_SET_REGION
 580                                 if (region) {
 581                                         msg_opt_add(&tx.msg, NMRP_O_DEV_REGION, &region, 2);
 582                                 }
 583 #endif
 584
 585                                 expect = NMRP_C_TFTP_UL_REQ;
 586
 587                                 printf("Received configuration request from %s.\n",
 588                                                 mac_to_str(rx.eh.ether_shost));
 589
 590                                 memcpy(tx.eh.ether_dhost, rx.eh.ether_shost, 6);
 591
 592                                 printf("Sending configuration: ip %s, mask %s.\n",
 593                                                 args->ipaddr, args->ipmask);
 594
 595                                 memcpy(arpmac, rx.eh.ether_shost, 6);
 596                                 memcpy(&arpip, &ipconf.addr, sizeof(ipconf.addr));
 597
 598                                 if (ethsock_arp_add(sock, arpmac, &arpip) != 0) {
 599                                         goto out;
 600                                 }
 601
 602                                 garp = 1;
 603
 604                                 break;
 605                         case NMRP_C_TFTP_UL_REQ:
 606                                 if (!upload_ok) {
 607                                         if (++ulreqs > 5) {
 608                                                 printf("Bailing out after %d upload requests.\n",
 609                                                                 ulreqs);
 610                                                 tx.msg.code = NMRP_C_CLOSE_REQ;
 611                                                 break;
 612                                         }
 613                                 } else {
 614                                         if (verbosity) {
 615                                                 printf("Ignoring extra upload request.\n");
 616                                         }
 617                                         ethsock_set_timeout(sock, args->ul_timeout);
 618                                         tx.msg.code = NMRP_C_KEEP_ALIVE_REQ;
 619                                         break;
 620                                 }
 621
 622                                 len = 0;
 623                                 filename = msg_opt_data(&rx.msg, NMRP_O_FILE_NAME, &len);
 624                                 if (filename) {
 625                                         if (!args->file_remote) {
 626                                                 args->file_remote = filename;
 627                                         }
 628                                         printf("Received upload request: filename '%.*s'.\n",
 629                                                         len, filename);
 630                                 } else if (!args->file_remote) {
 631                                         args->file_remote = args->file_local;
 632                                         printf("Received upload request with empty filename.\n");
 633                                 }
 634
 635                                 status = 0;
 636
 637                                 if (args->tftpcmd) {
 638                                         printf("Executing '%s' ... \n", args->tftpcmd);
 639                                         setenv("IP", inet_ntoa(ipconf.addr), 1);
 640                                         setenv("MAC", mac_to_str(rx.eh.ether_shost), 1);
 641                                         setenv("NETMASK", inet_ntoa(ipconf.mask), 1);
 642                                         status = system(args->tftpcmd);
 643                                 }
 644
 645                                 if (!status && args->file_local) {
 646                                         if (!autoip) {
 647                                                 status = is_valid_ip(sock, &ipconf.addr, &ipconf.mask);
 648                                                 if (status < 0) {
 649                                                         goto out;
 650                                                 } else if (!status) {
 651                                                         printf("IP address of %s has changed. Please assign a "
 652                                                                         "static ip to the interface.\n", args->intf);
 653                                                         tx.msg.code = NMRP_C_CLOSE_REQ;
 654                                                         break;
 655                                                 }
 656                                         }
 657
 658                                         if (verbosity) {
 659                                                 printf("Using remote filename '%s'.\n",
 660                                                                 args->file_remote);
 661                                         }
 662
 663                                         if (!strcmp(args->file_local, "-")) {
 664                                                 printf("Uploading from stdin ... ");
 665                                         } else {
 666                                                 printf("Uploading %s ... ", leafname(args->file_local));
 667                                         }
 668                                         fflush(stdout);
 669                                         status = tftp_put(args);
 670                                 }
 671
 672                                 if (!status) {
 673                                         printf("OK\nWaiting for remote to respond.\n");
 674                                         upload_ok = 1;
 675                                         ethsock_set_timeout(sock, args->ul_timeout);
 676                                         tx.msg.code = NMRP_C_KEEP_ALIVE_REQ;
 677                                         expect = NMRP_C_NONE;
 678                                 } else if (status == -2) {
 679                                         expect = NMRP_C_TFTP_UL_REQ;
 680                                 } else {
 681                                         goto out;
 682                                 }
 683
 684                                 break;
 685                         case NMRP_C_KEEP_ALIVE_REQ:
 686                                 tx.msg.code = NMRP_C_KEEP_ALIVE_ACK;
 687                                 ethsock_set_timeout(sock, args->ul_timeout);
 688                                 printf("Received keep-alive request.\n");
 689                                 break;
 690                         case NMRP_C_CLOSE_REQ:
 691                                 tx.msg.code = NMRP_C_CLOSE_ACK;
 692                                 break;
 693                         case NMRP_C_CLOSE_ACK:
 694                                 status = 0;
 695                                 goto out;
 696                         default:
 697                                 fprintf(stderr, "Unknown message code 0x%02x!\n",
 698                                                 rx.msg.code);
 699                                 msg_dump(&rx.msg, 0);
 700                 }
 701
 702                 if (tx.msg.code != NMRP_C_NONE) {
 703                         msg_hton(&tx.msg);
 704
 705                         if (pkt_send(sock, &tx) < 0) {
 706                                 perror("sendto");
 707                                 goto out;
 708                         }
 709
 710                         if (tx.msg.code == NMRP_C_CLOSE_REQ) {
 711                                 goto out;
 712                         }
 713                 }
 714
 715                 if (rx.msg.code == NMRP_C_CLOSE_REQ) {
 716                         printf("Remote finished. Closing connection.\n");
 717                         break;
 718                 }
 719
 720                 status = pkt_recv(sock, &rx);
 721                 if (status) {
 722                         if (status == 2) {
 723                                 fprintf(stderr, "Timeout while waiting for %s.\n",
 724                                                 msg_code_str(expect));
 725                         }
 726                         goto out;
 727                 }
 728
 729                 ethsock_set_timeout(sock, args->rx_timeout);
 730
 731         } while (1);
 732
 733         status = 0;
 734
 735         if (ulreqs) {
 736                 printf("Reboot your device now.\n");
 737         } else {
 738                 printf("No upload request received.\n");
 739         }
 740
 741 out:
 742         signal(SIGINT, sigh_orig);
 743         gsock = NULL;
 744         ethsock_arp_del(sock, arpmac, &arpip);
 745         ethsock_ip_del(sock, &gundo);
 746         ethsock_close(sock);
 747         return status;
 748 }