listen.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4 #include <errno.h>
   5 #include <string.h>
   6 #include <sys/types.h>
   7 #include <sys/socket.h>
   8 #include <netinet/in.h>
   9 #include <netdb.h>
  10 #include <arpa/inet.h>
  11 #include <sys/wait.h>
  12 #include <signal.h>
  13 #include <libnotify/notify.h>
  14
  15 #define PORT "3490"  // the port users will be connecting to
  16
  17 #define BACKLOG 10       // how many pending connections queue will hold
  18
  19 void sigchld_handler(int s)
  20 {
  21         while(waitpid(-1, NULL, WNOHANG) > 0);
  22 }
  23
  24 // get sockaddr, IPv4
  25 void *get_in_addr(struct sockaddr *sa)
  26 {
  27         if (sa->sa_family == AF_INET) {
  28                 return &(((struct sockaddr_in*)sa)->sin_addr);
  29         }
  30 }
  31
  32 int main(void)
  33 {
  34         int sockfd, activefd;  // listen on sockfd, new connection on activefd
  35         struct addrinfo hints, *servinfo, *p;
  36         struct sockaddr_storage their_addr; // connector's address information
  37         socklen_t sin_size;
  38         struct sigaction sa;
  39         int yes=1;
  40         char source[INET6_ADDRSTRLEN];
  41 //    char CLIENT_IP[15] = "107.21.205.69\0";
  42         int rv;
  43
  44         memset(&hints, 0, sizeof hints); // make sure the struct is empty
  45         hints.ai_family = AF_INET; // IPv4
  46         hints.ai_socktype = SOCK_STREAM;
  47         hints.ai_flags = AI_PASSIVE; // use my IP
  48
  49         if ((rv = getaddrinfo(NULL, PORT, &hints, &servinfo)) != 0) {
  50                 fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
  51                 return 1;
  52         }
  53
  54     // servinfo now points to a linked list of 1 or more struct addrinfos
  55
  56         // loop through all the results and bind to the first we can
  57         for(p = servinfo; p != NULL; p = p->ai_next) {
  58                 if ((sockfd = socket(p->ai_family, p->ai_socktype,
  59                                 p->ai_protocol)) == -1) {
  60                         perror("irssi-notify: socket");
  61                         continue;
  62                 }
  63
  64                 if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes,
  65                                 sizeof(int)) == -1) {
  66                         perror("setsockopt");
  67                         exit(1);
  68                 }
  69
  70                 if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
  71                         close(sockfd);
  72                         perror("irssi-notify: bind");
  73                         continue;
  74                 }
  75
  76                 break;
  77         }
  78
  79         if (p == NULL)  {
  80                 fprintf(stderr, "irssi-notify: failed to bind\n");
  81                 return 2;
  82         }
  83
  84         freeaddrinfo(servinfo); // all done with this structure
  85
  86         if (listen(sockfd, BACKLOG) == -1) {
  87                 perror("listen");
  88                 exit(1);
  89         }
  90
  91         sa.sa_handler = sigchld_handler; // reap all dead processes
  92         sigemptyset(&sa.sa_mask);
  93         sa.sa_flags = SA_RESTART;
  94         if (sigaction(SIGCHLD, &sa, NULL) == -1) {
  95                 perror("sigaction");
  96                 exit(1);
  97         }
  98
  99         printf("irssi-notify: waiting for connections...\n");
 100
 101         while(1) {  // main accept() loop
 102                 sin_size = sizeof their_addr;
 103                 activefd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size);
 104                 if (activefd == -1) {
 105                         perror("accept");
 106                         continue;
 107                 }
 108
 109                 inet_ntop(their_addr.ss_family,
 110                         get_in_addr((struct sockaddr *)&their_addr),
 111                         source, sizeof source);
 112
 113         if (strcmp(source, "50.16.219.8") != 0 &&
 114                 strcmp(source, "127.0.0.1") != 0){
 115             close(activefd);
 116             continue;
 117         }
 118
 119                 if (!fork()) { // this is the child process
 120                         close(sockfd); // child doesn't need the listener
 121             char buf[4096];
 122             if (recv(activefd, buf, 99, 0) == -1) {
 123                 perror("recv");
 124                 exit(1);
 125             }
 126             buf[4096] = '\0';
 127             printf("irssi-notify: recieved '%s'\n", buf);
 128             notify_init("irssi-notify");
 129             NotifyNotification * notification =
 130                 notify_notification_new("", buf, "irssi-notify");
 131             notify_notification_show(notification, NULL);
 132                         close(activefd);
 133                         exit(0);
 134                 }
 135                 close(activefd);
 136         }
 137
 138         return 0;
 139 }