nsctl.c

   1 /* l2tpns plugin control */
   2
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <unistd.h>
   6 #include <errno.h>
   7 #include <string.h>
   8 #include <netdb.h>
   9 #include <signal.h>
  10
  11 #include "l2tpns.h"
  12 #include "control.h"
  13
  14 struct {
  15     char *command;
  16     char *usage;
  17     int action;
  18 } builtins[] = {
  19     { "load_plugin", " PLUGIN                          Load named plugin",              NSCTL_REQ_LOAD },
  20     { "unload_plugin", " PLUGIN                        Unload named plugin",            NSCTL_REQ_UNLOAD },
  21     { "help", "                                        List available commands",        NSCTL_REQ_HELP },
  22     { 0 }
  23 };
  24
  25 static int debug = 0;
  26 static int timeout = 2; // 2 seconds
  27 static char *me;
  28
  29 #define USAGE() fprintf(stderr, "Usage: %s [-d] [-h HOST[:PORT]] [-t TIMEOUT] COMMAND [ARG ...]\n", me)
  30
  31 static struct nsctl *request(char *host, int port, int type, int argc, char *argv[]);
  32
  33 int main(int argc, char *argv[])
  34 {
  35     int req_type = 0;
  36     char *host = 0;
  37     int port;
  38     int i;
  39     char *p;
  40     struct nsctl *res;
  41
  42     if ((p = strrchr((me = argv[0]), '/')))
  43         me = p + 1;
  44
  45     opterr = 0;
  46     while ((i = getopt(argc, argv, "dh:t:")) != -1)
  47         switch (i)
  48         {
  49         case 'd':
  50             debug++;
  51             break;
  52
  53         case 'h':
  54             host = optarg;
  55             break;
  56
  57         case 't':
  58             timeout = atoi(optarg);
  59             break;
  60
  61         default:
  62             USAGE();
  63             return EXIT_FAILURE;
  64         }
  65
  66     argc -= optind;
  67     argv += optind;
  68
  69     if (argc < 1 || !argv[0][0])
  70     {
  71         USAGE();
  72         return EXIT_FAILURE;
  73     }
  74
  75     if (!host)
  76         host = "127.0.0.1";
  77
  78     if ((p = strchr(host, ':')))
  79     {
  80         port = atoi(p + 1);
  81         if (!port)
  82         {
  83             fprintf(stderr, "%s: invalid port `%s'\n", me, p + 1);
  84             return EXIT_FAILURE;
  85         }
  86
  87         *p = 0;
  88     }
  89     else
  90     {
  91         port = NSCTL_PORT;
  92     }
  93
  94     for (i = 0; !req_type && builtins[i].command; i++)
  95         if (!strcmp(argv[0], builtins[i].command))
  96             req_type = builtins[i].action;
  97
  98     if (req_type == NSCTL_REQ_HELP)
  99     {
 100         printf("Available commands:\n");
 101         for (i = 0; builtins[i].command; i++)
 102             printf("  %s%s\n", builtins[i].command, builtins[i].usage);
 103     }
 104
 105     if (req_type)
 106     {
 107         argc--;
 108         argv++;
 109     }
 110     else
 111     {
 112         req_type = NSCTL_REQ_CONTROL;
 113     }
 114
 115     if ((res = request(host, port, req_type, argc, argv)))
 116     {
 117         FILE *stream = stderr;
 118         int status = EXIT_FAILURE;
 119
 120         if (res->type == NSCTL_RES_OK)
 121         {
 122             stream = stdout;
 123             status = EXIT_SUCCESS;
 124         }
 125
 126         for (i = 0; i < res->argc; i++)
 127             fprintf(stream, "%s\n", res->argv[i]);
 128
 129         return status;
 130     }
 131
 132     return EXIT_FAILURE;
 133 }
 134
 135 static void sigalrm_handler(int sig) { }
 136
 137 static struct nsctl *request(char *host, int port, int type, int argc, char *argv[])
 138 {
 139     static struct nsctl res;
 140     struct sockaddr_in peer;
 141     socklen_t len = sizeof(peer);
 142     struct hostent *h = gethostbyname(host);
 143     int fd;
 144     char buf[NSCTL_MAX_PKT_SZ];
 145     int sz;
 146     char *err;
 147
 148     if (!h || h->h_addrtype != AF_INET)
 149     {
 150         fprintf(stderr, "%s: invalid host `%s'\n", me, host);
 151         return 0;
 152     }
 153
 154     if ((fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
 155     {
 156         fprintf(stderr, "%s: can't create udp socket (%s)\n", me, strerror(errno));
 157         return 0;
 158     }
 159
 160     memset(&peer, 0, len);
 161     peer.sin_family = AF_INET;
 162     peer.sin_port = htons(port);
 163     memcpy(&peer.sin_addr.s_addr, h->h_addr, sizeof(peer.sin_addr.s_addr));
 164
 165     if (connect(fd, (struct sockaddr *) &peer, sizeof(peer)) < 0)
 166     {
 167         fprintf(stderr, "%s: udp connect failed (%s)\n", me, strerror(errno));
 168         return 0;
 169     }
 170
 171     if ((sz = pack_control(buf, sizeof(buf), type, argc, argv)) < 0)
 172     {
 173         fprintf(stderr, "%s: error packing request\n", me);
 174         return 0;
 175     }
 176
 177     if (debug)
 178     {
 179         struct nsctl req;
 180         if (unpack_control(&req, buf, sz) == type)
 181         {
 182             fprintf(stderr, "Sending ");
 183             dump_control(&req, stderr);
 184         }
 185     }
 186
 187     if (send(fd, buf, sz, 0) < 0)
 188     {
 189         fprintf(stderr, "%s: error sending request (%s)\n", me, strerror(errno));
 190         return 0;
 191     }
 192
 193     /* set timer */
 194     if (timeout)
 195     {
 196         struct sigaction alrm;
 197         alrm.sa_handler = sigalrm_handler;
 198         sigemptyset(&alrm.sa_mask);
 199         alrm.sa_flags = 0;
 200
 201         sigaction(SIGALRM, &alrm, 0);
 202         alarm(timeout);
 203     }
 204
 205     sz = recv(fd, buf, sizeof(buf), 0);
 206     alarm(0);
 207
 208     if (sz < 0)
 209     {
 210         fprintf(stderr, "%s: error receiving response (%s)\n", me,
 211             errno == EINTR ? "timed out" : strerror(errno));
 212
 213         return 0;
 214     }
 215
 216     if ((type = unpack_control(&res, buf, sz)) > 0 && type & NSCTL_RESPONSE)
 217     {
 218         if (debug)
 219         {
 220             fprintf(stderr, "Received ");
 221             dump_control(&res, stderr);
 222         }
 223
 224         return &res;
 225     }
 226
 227     err = "unknown error";
 228     switch (type)
 229     {
 230     case NSCTL_ERR_SHORT:  err = "short packet"; break;
 231     case NSCTL_ERR_LONG:   err = "extra data";   break;
 232     case NSCTL_ERR_MAGIC:  err = "bad magic";    break;
 233     case NSCTL_ERR_TYPE:   err = "invalid type"; break;
 234     }
 235
 236     fprintf(stderr, "%s: %s\n", me, err);
 237     return 0;
 238 }