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      1 /*-
      2  * Copyright (c) 1999 Brian Somers <brian (at) Awfulhak.org>
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     24  * SUCH DAMAGE.
     25  *
     26  * $FreeBSD: src/usr.sbin/ppp/udp.c,v 1.20.26.1 2010/12/21 17:10:29 kensmith Exp $
     27  */
     28 
     29 #include <sys/types.h>
     30 #include <sys/socket.h>
     31 #include <netinet/in.h>
     32 #include <arpa/inet.h>
     33 #include <netdb.h>
     34 
     35 #include <errno.h>
     36 #include <stdio.h>
     37 #include <stdlib.h>
     38 #include <string.h>
     39 #include <sysexits.h>
     40 #include <sys/stat.h>
     41 #include <sys/uio.h>
     42 #include <termios.h>
     43 #include <unistd.h>
     44 
     45 #include "layer.h"
     46 #include "defs.h"
     47 #include "mbuf.h"
     48 #include "log.h"
     49 #include "timer.h"
     50 #include "lqr.h"
     51 #include "hdlc.h"
     52 #include "throughput.h"
     53 #include "fsm.h"
     54 #include "lcp.h"
     55 #include "ccp.h"
     56 #include "link.h"
     57 #include "async.h"
     58 #include "descriptor.h"
     59 #include "physical.h"
     60 #include "main.h"
     61 #include "udp.h"
     62 
     63 
     64 #define UDP_CONNECTED		1
     65 #define UDP_UNCONNECTED		2
     66 #define UDP_MAYBEUNCONNECTED	3
     67 
     68 struct udpdevice {
     69   struct device dev;		/* What struct physical knows about */
     70   struct sockaddr_in sock;	/* peer address */
     71   unsigned connected : 2;	/* Have we connect()d ? */
     72 };
     73 
     74 #define device2udp(d) ((d)->type == UDP_DEVICE ? (struct udpdevice *)d : NULL)
     75 
     76 unsigned
     77 udp_DeviceSize(void)
     78 {
     79   return sizeof(struct udpdevice);
     80 }
     81 
     82 static ssize_t
     83 udp_Sendto(struct physical *p, const void *v, size_t n)
     84 {
     85   struct udpdevice *dev = device2udp(p->handler);
     86   int ret;
     87 
     88   switch (dev->connected) {
     89     case UDP_CONNECTED:
     90       ret = write(p->fd, v, n);
     91       break;
     92 
     93     case UDP_UNCONNECTED:
     94     default:
     95       ret = sendto(p->fd, v, n, 0, (struct sockaddr *)&dev->sock,
     96                    sizeof dev->sock);
     97       break;
     98   }
     99   if (dev->connected == UDP_MAYBEUNCONNECTED) {
    100     if (ret == -1 && errno == EISCONN) {
    101       dev->connected = UDP_CONNECTED;
    102       ret = write(p->fd, v, n);
    103     } else
    104       dev->connected = UDP_UNCONNECTED;
    105   }
    106 
    107   return ret;
    108 }
    109 
    110 static ssize_t
    111 udp_Recvfrom(struct physical *p, void *v, size_t n)
    112 {
    113   struct udpdevice *dev = device2udp(p->handler);
    114   int sz, ret;
    115 
    116   if (dev->connected == UDP_CONNECTED)
    117     return read(p->fd, v, n);
    118 
    119   sz = sizeof dev->sock;
    120   ret = recvfrom(p->fd, v, n, 0, (struct sockaddr *)&dev->sock, &sz);
    121 
    122   if (*p->name.full == '\0') {
    123     snprintf(p->name.full, sizeof p->name.full, "%s:%d/udp",
    124              inet_ntoa(dev->sock.sin_addr), ntohs(dev->sock.sin_port));
    125     p->name.base = p->name.full;
    126   }
    127 
    128   return ret;
    129 }
    130 
    131 static void
    132 udp_Free(struct physical *p)
    133 {
    134   struct udpdevice *dev = device2udp(p->handler);
    135 
    136   free(dev);
    137 }
    138 
    139 static void
    140 udp_device2iov(struct device *d, struct iovec *iov, int *niov,
    141                int maxiov __unused, int *auxfd __unused, int *nauxfd __unused)
    142 {
    143   int sz = physical_MaxDeviceSize();
    144 
    145   iov[*niov].iov_base = realloc(d, sz);
    146   if (iov[*niov].iov_base == NULL) {
    147     log_Printf(LogALERT, "Failed to allocate memory: %d\n", sz);
    148     AbortProgram(EX_OSERR);
    149   }
    150   iov[*niov].iov_len = sz;
    151   (*niov)++;
    152 }
    153 
    154 static const struct device baseudpdevice = {
    155   UDP_DEVICE,
    156   "udp",
    157   0,
    158   { CD_NOTREQUIRED, 0 },
    159   NULL,
    160   NULL,
    161   NULL,
    162   NULL,
    163   NULL,
    164   NULL,
    165   NULL,
    166   udp_Free,
    167   udp_Recvfrom,
    168   udp_Sendto,
    169   udp_device2iov,
    170   NULL,
    171   NULL,
    172   NULL
    173 };
    174 
    175 struct device *
    176 udp_iov2device(int type, struct physical *p, struct iovec *iov, int *niov,
    177                int maxiov __unused, int *auxfd __unused, int *nauxfd __unused)
    178 {
    179   if (type == UDP_DEVICE) {
    180     struct udpdevice *dev = (struct udpdevice *)iov[(*niov)++].iov_base;
    181 
    182     dev = realloc(dev, sizeof *dev);	/* Reduce to the correct size */
    183     if (dev == NULL) {
    184       log_Printf(LogALERT, "Failed to allocate memory: %d\n",
    185                  (int)(sizeof *dev));
    186       AbortProgram(EX_OSERR);
    187     }
    188 
    189     /* Refresh function pointers etc */
    190     memcpy(&dev->dev, &baseudpdevice, sizeof dev->dev);
    191 
    192     physical_SetupStack(p, dev->dev.name, PHYSICAL_FORCE_SYNC);
    193     return &dev->dev;
    194   }
    195 
    196   return NULL;
    197 }
    198 
    199 static struct udpdevice *
    200 udp_CreateDevice(struct physical *p, char *host, char *port)
    201 {
    202   struct udpdevice *dev;
    203   struct servent *sp;
    204 
    205   if ((dev = malloc(sizeof *dev)) == NULL) {
    206     log_Printf(LogWARN, "%s: Cannot allocate a udp device: %s\n",
    207                p->link.name, strerror(errno));
    208     return NULL;
    209   }
    210 
    211   dev->sock.sin_family = AF_INET;
    212   dev->sock.sin_addr = GetIpAddr(host);
    213   if (dev->sock.sin_addr.s_addr == INADDR_NONE) {
    214     log_Printf(LogWARN, "%s: %s: unknown host\n", p->link.name, host);
    215     free(dev);
    216     return NULL;
    217   }
    218   dev->sock.sin_port = htons(atoi(port));
    219   if (dev->sock.sin_port == 0) {
    220     sp = getservbyname(port, "udp");
    221     if (sp)
    222       dev->sock.sin_port = sp->s_port;
    223     else {
    224       log_Printf(LogWARN, "%s: %s: unknown service\n", p->link.name, port);
    225       free(dev);
    226       return NULL;
    227     }
    228   }
    229 
    230   log_Printf(LogPHASE, "%s: Connecting to %s:%s/udp\n", p->link.name,
    231              host, port);
    232 
    233   p->fd = socket(PF_INET, SOCK_DGRAM, 0);
    234   if (p->fd >= 0) {
    235     log_Printf(LogDEBUG, "%s: Opened udp socket %s\n", p->link.name,
    236                p->name.full);
    237     if (connect(p->fd, (struct sockaddr *)&dev->sock, sizeof dev->sock) == 0) {
    238       dev->connected = UDP_CONNECTED;
    239       return dev;
    240     } else
    241       log_Printf(LogWARN, "%s: connect: %s\n", p->name.full, strerror(errno));
    242   } else
    243     log_Printf(LogWARN, "%s: socket: %s\n", p->name.full, strerror(errno));
    244 
    245   close(p->fd);
    246   p->fd = -1;
    247   free(dev);
    248 
    249   return NULL;
    250 }
    251 
    252 struct device *
    253 udp_Create(struct physical *p)
    254 {
    255   char *cp, *host, *port, *svc;
    256   struct udpdevice *dev;
    257 
    258   dev = NULL;
    259   if (p->fd < 0) {
    260     if ((cp = strchr(p->name.full, ':')) != NULL && !strchr(cp + 1, ':')) {
    261       *cp = '\0';
    262       host = p->name.full;
    263       port = cp + 1;
    264       svc = strchr(port, '/');
    265       if (svc && strcasecmp(svc, "/udp")) {
    266         *cp = ':';
    267         return NULL;
    268       }
    269       if (svc) {
    270         p->fd--;     /* We own the device but maybe can't use it - change fd */
    271         *svc = '\0';
    272       }
    273 
    274       if (*host && *port)
    275         dev = udp_CreateDevice(p, host, port);
    276 
    277       *cp = ':';
    278       if (svc)
    279         *svc = '/';
    280     }
    281   } else {
    282     /* See if we're a connected udp socket */
    283     struct stat st;
    284 
    285     if (fstat(p->fd, &st) != -1 && (st.st_mode & S_IFSOCK)) {
    286       int type, sz;
    287 
    288       sz = sizeof type;
    289       if (getsockopt(p->fd, SOL_SOCKET, SO_TYPE, &type, &sz) == -1) {
    290         log_Printf(LogPHASE, "%s: Link is a closed socket !\n", p->link.name);
    291         close(p->fd);
    292         p->fd = -1;
    293         return NULL;
    294       }
    295 
    296       if (sz == sizeof type && type == SOCK_DGRAM) {
    297         struct sockaddr_in sock;
    298         struct sockaddr *sockp = (struct sockaddr *)&sock;
    299 
    300         if ((dev = malloc(sizeof *dev)) == NULL) {
    301           log_Printf(LogWARN, "%s: Cannot allocate a udp device: %s\n",
    302                      p->link.name, strerror(errno));
    303           return NULL;
    304         }
    305 
    306         if (getpeername(p->fd, sockp, &sz) == 0) {
    307           log_Printf(LogPHASE, "%s: Link is a connected udp socket\n",
    308                      p->link.name);
    309           dev->connected = UDP_CONNECTED;
    310 	} else {
    311           log_Printf(LogPHASE, "%s: Link is a disconnected udp socket\n",
    312                      p->link.name);
    313 
    314           dev->connected = UDP_MAYBEUNCONNECTED;
    315 
    316           if (p->link.lcp.cfg.openmode != OPEN_PASSIVE) {
    317             log_Printf(LogPHASE, "%s:   Changing openmode to PASSIVE\n",
    318                        p->link.name);
    319             p->link.lcp.cfg.openmode = OPEN_PASSIVE;
    320           }
    321         }
    322       }
    323     }
    324   }
    325 
    326   if (dev) {
    327     memcpy(&dev->dev, &baseudpdevice, sizeof dev->dev);
    328     physical_SetupStack(p, dev->dev.name, PHYSICAL_FORCE_SYNC);
    329     if (p->cfg.cd.necessity != CD_DEFAULT)
    330       log_Printf(LogWARN, "Carrier settings ignored\n");
    331     return &dev->dev;
    332   }
    333 
    334   return NULL;
    335 }
    336