initial commit

1 files changed, 99 insertions, 0 deletions

diff --git a/wol-proxyd.c b/wol-proxyd.c
new file mode 100644
index 0000000..b36ce98
--- /dev/null
+++ b/wol-proxyd.c
@@ -0,0 +1,99 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <netdb.h>
+#include <ifaddrs.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+static void die(const char *str)
+{
+	fprintf(stderr, "%s\n", str);
+	exit(1);
+}
+
+static is_same_subnet(struct sockaddr_in *a, struct sockaddr_in *b,
+		      struct sockaddr_in *mask)
+{
+	if (a->sin_family != b->sin_family)
+		return 0;
+	return ((a->sin_addr.s_addr & mask->sin_addr.s_addr)
+		== (b->sin_addr.s_addr & mask->sin_addr.s_addr));
+}
+
+static int get_bcast_addr(const char *iface, struct sockaddr_in *src,
+			  struct sockaddr_in *bcast)
+{
+	struct ifaddrs *ifaddr, *ifa;
+	char host[NI_MAXHOST], bhost[NI_MAXHOST];
+	int ret = 0;
+
+	if (getifaddrs(&ifaddr) == -1)
+		die("getifaddrs");
+
+	for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
+		if (ifa->ifa_addr == NULL
+		    || ifa->ifa_addr->sa_family != AF_INET
+		    || (strcmp(iface, ifa->ifa_name) != 0))
+			continue;
+
+		/* dont forward broadcast from our own subnet(s) */
+		if (is_same_subnet((struct sockaddr_in *)ifa->ifa_addr, src,
+				   (struct sockaddr_in *)ifa->ifa_netmask))
+			continue;
+
+		memcpy(bcast, ifa->ifa_ifu.ifu_broadaddr,
+			sizeof(struct sockaddr_in));
+		ret = sizeof(struct sockaddr_in);
+		break;
+	}
+	freeifaddrs(ifaddr);
+	return ret;
+}
+
+static int run_proxy(const char *iface, int port)
+{
+	struct sockaddr_in src, dst;
+	char buf[256];
+	int fd, n;
+	socklen_t addrlen;
+
+	fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+	if (fd < 0)
+		die("socket");
+
+	memset(&src, 0, sizeof(src));
+	src.sin_family = AF_INET;
+	src.sin_port = htons(port);
+	src.sin_addr.s_addr = htonl(INADDR_ANY);
+
+	if (bind(fd, (struct sockaddr *)&src, sizeof(src)) < 0)
+		die("bind");
+
+	while (1) {
+		n = recvfrom(fd, buf, sizeof(buf), 0, (struct sockaddr *)&src,
+			     &addrlen);
+		if (n < 0)
+			die("recvfrom");
+
+		if (get_bcast_addr(iface, &src, &dst)) {
+			dst.sin_port = htons(port);
+			sendto(fd, buf, n, 0, (struct sockaddr *) &dst,
+			       sizeof(dst));
+		}
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	int c;
+	int port = 9;
+	const char *iface = NULL;
+	if (argc > 1)
+		iface = argv[1];
+	run_proxy(iface, port);
+}