Merge pull request #2 from kubo/scream-pulse-set-nic-name

Add an option to set network interface name.

Receivers/pulseaudio/Makefile

@@ -1,4 +1,5 @@
 CC=gcc
+CFLAGS = -Wall
 
-scream-pulse:
-	$(CC) -o scream-pulse scream-pulse.c -lpulse-simple -lpulse
+scream-pulse: scream-pulse.c
+	$(CC) $(CFLAGS) -o scream-pulse scream-pulse.c -lpulse-simple -lpulse

Receivers/pulseaudio/README.md

@@ -0,0 +1,28 @@
+# scream-pulse
+
+scream-pulse is a scream receiver using pulseaudio as audio output.
+
+## Compile
+
+You need pulseaudio headers in advance.
+
+```shell
+$ sudo yum install pulseaudio-libs-devel # Redhat, CentOS, etc.
+or
+$ sudo apt-get install libpulse-dev # Debian, Ubuntu, etc.
+```
+
+Run `make` command.
+
+## Usage
+
+```shell
+$ scream-pulse
+```
+
+If your machine has more than one network interface, you may need to
+set the interface name which receives scream packets.
+
+```shell
+$ scream-pulse -i eth0
+```

Receivers/pulseaudio/scream-pulse.c

@@ -1,17 +1,67 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <pulse/simple.h>
 #include <pulse/error.h>
 
+#include <unistd.h>
 #include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <net/if.h>
 #include <netinet/in.h>
+#include <arpa/inet.h>
 
 #define MULTICAST_TARGET "239.255.77.77"
 #define MULTICAST_PORT 4010
 #define MAX_SO_PACKETSIZE 1764
 #define MIN_PA_PACKETSIZE MAX_SO_PACKETSIZE
 #define BUFFER_SIZE MIN_PA_PACKETSIZE * 2
 
+static void show_usage(const char *arg0)
+{
+  fprintf(stderr, "Usage: %s [-i interface_name_or_address]\n",
+	  arg0);
+  exit(1);
+}
+
+static in_addr_t get_interface(const char *name)
+{
+  int sockfd = socket(AF_INET,SOCK_DGRAM,0);
+  struct ifreq ifr;
+  in_addr_t addr = inet_addr(name);
+  struct if_nameindex *ni;
+  int i;
+
+  if (addr != INADDR_NONE) {
+    return addr;
+  }
+
+  if (strlen(name) >= sizeof(ifr.ifr_name)) {
+    fprintf(stderr, "Too long interface name: %s\n\n", name);
+    goto error_exit;
+  }
+  strcpy(ifr.ifr_name, name);
+
+  sockfd = socket(AF_INET,SOCK_DGRAM,0);
+  if (ioctl(sockfd, SIOCGIFADDR, &ifr) != 0) {
+    fprintf(stderr, "Invalid interface: %s\n\n", name);
+    goto error_exit;
+  }
+  close(sockfd);
+  return ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr;
+
+error_exit:
+  ni = if_nameindex();
+  fprintf(stderr, "Available interfaces:\n");
+  for (i = 0; ni[i].if_name != NULL; i++) {
+    strcpy(ifr.ifr_name, ni[i].if_name);
+    if (ioctl(sockfd, SIOCGIFADDR, &ifr) == 0) {
+      fprintf(stderr, "  %-10s (%s)\n", ni[i].if_name, inet_ntoa(((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr));
+    }
+  }
+  exit(1);
+}
+
 int main(int argc, char*argv[]) {
   int sockfd, error;
   ssize_t n;
@@ -21,6 +71,22 @@ int main(int argc, char*argv[]) {
   pa_simple *s;
   pa_sample_spec ss;
   unsigned char buf[BUFFER_SIZE];
+  in_addr_t interface = INADDR_ANY;
+  int opt;
+
+  while ((opt = getopt(argc, argv, "i:")) != -1) {
+    switch (opt) {
+    case 'i':
+      interface = get_interface(optarg);
+      break;
+    default:
+      show_usage(argv[0]);
+    }
+  }
+  if (optind < argc) {
+    fprintf(stderr, "Expected argument after options\n");
+    show_usage(argv[0]);
+  }
 
   ss.format = PA_SAMPLE_S16NE;
   ss.channels = 2;
@@ -46,7 +112,7 @@ int main(int argc, char*argv[]) {
   bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
 
   imreq.imr_multiaddr.s_addr = inet_addr(MULTICAST_TARGET);
-  imreq.imr_interface.s_addr = INADDR_ANY;
+  imreq.imr_interface.s_addr = interface;
 
   setsockopt(sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, 
             (const void *)&imreq, sizeof(struct ip_mreq));
@@ -68,4 +134,5 @@ int main(int argc, char*argv[]) {
 
   BAIL:
   if (s) pa_simple_free(s);
+  return 0;
 };