Initial

3 files changed, 192 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..fd68f90
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,36 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=udp-broadcast
+PKG_VERSION:=1.0.0
+PKG_RELEASE:=1
+
+PKG_BUILD_DIR:=$(BUILD_DIR)/udp-broadcast-$(PKG_VERSION)
+PKG_SOURCE:=udp-broadcas-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=@SF/udp-broadcas
+PKG_MD5SUM:=9b7dc52656f5cbec846a7ba3299f73bd
+PKG_CAT:=zcat
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/bridge
+  SECTION:=base
+  CATEGORY:=Network
+  DEFAULT:=y
+  TITLE:=UDP broadcast utility
+  DESCRIPTION:=UDP broadcast utility\\\
+    send and recive udp broadcast\\\
+    form a larger network.
+  URL:=http://www.freifunk-jena.de/
+endef
+
+define Build/Configure
+  $(call Build/Configure/Default,--with-linux-headers=$(LINUX_DIR))
+endef
+
+define Package/bridge/install
+        $(INSTALL_DIR) $(1)/usr/sbin
+        $(INSTALL_BIN) $(PKG_BUILD_DIR)/broadcast $(1)/usr/sbin/
+        $(INSTALL_BIN) $(PKG_BUILD_DIR)/listener $(1)/usr/sbin/
+endef
+
+$(eval $(call BuildPackage,udp-broadcast))
diff --git a/broadcaster.c b/broadcaster.c
new file mode 100644
index 0000000..0e4eef5
--- /dev/null
+++ b/broadcaster.c
@@ -0,0 +1,67 @@
+/*
+** broadcaster.c -- a datagram "client" like talker.c, except
+**                  this one can broadcast
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+#define SERVERPORT 4950    // the port users will be connecting to
+
+int main(int argc, char *argv[])
+{
+    int sockfd;
+    struct sockaddr_in their_addr; // connector's address information
+    struct hostent *he;
+    int numbytes;
+    int broadcast = 1;
+    //char broadcast = '1'; // if that doesn't work, try this
+
+    if (argc != 3) {
+        fprintf(stderr,"usage: broadcaster hostname message\n");
+        exit(1);
+    }
+
+    if ((he=gethostbyname(argv[1])) == NULL) {  // get the host info
+        perror("gethostbyname");
+        exit(1);
+    }
+
+    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
+        perror("socket");
+        exit(1);
+    }
+
+    // this call is what allows broadcast packets to be sent:
+    if (setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &broadcast,
+        sizeof broadcast) == -1) {
+        perror("setsockopt (SO_BROADCAST)");
+        exit(1);
+    }
+
+    their_addr.sin_family = AF_INET;     // host byte order
+    their_addr.sin_port = htons(SERVERPORT); // short, network byte order
+    their_addr.sin_addr = *((struct in_addr *)he->h_addr);
+    memset(their_addr.sin_zero, '\0', sizeof their_addr.sin_zero);
+
+    if ((numbytes=sendto(sockfd, argv[2], strlen(argv[2]), 0,
+             (struct sockaddr *)&their_addr, sizeof their_addr)) == -1) {
+        perror("sendto");
+        exit(1);
+    }
+
+    printf("sent %d bytes to %s\n", numbytes,
+        inet_ntoa(their_addr.sin_addr));
+
+    close(sockfd);
+
+    return 0;
+}
diff --git a/listener.c b/listener.c
new file mode 100644
index 0000000..fa9f0c1
--- /dev/null
+++ b/listener.c
@@ -0,0 +1,89 @@
+/*
+** listener.c -- a datagram sockets "server" demo
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+#define MYPORT "4950"    // the port users will be connecting to
+
+#define MAXBUFLEN 100
+
+// get sockaddr, IPv4 or IPv6:
+void *get_in_addr(struct sockaddr *sa)
+{
+    if (sa->sa_family == AF_INET) {
+        return &(((struct sockaddr_in*)sa)->sin_addr);
+    }
+
+    return &(((struct sockaddr_in6*)sa)->sin6_addr);
+}
+
+int main(void)
+{
+    int sockfd;
+    struct addrinfo hints, *servinfo, *p;
+    int rv;
+    int numbytes;
+    struct sockaddr_storage their_addr;
+    char buf[MAXBUFLEN];
+    socklen_t addr_len;
+    char s[INET6_ADDRSTRLEN];
+
+    memset(&hints, 0, sizeof hints);
+    hints.ai_family = AF_UNSPEC; // set to AF_INET to force IPv4
+    hints.ai_socktype = SOCK_DGRAM;
+    hints.ai_flags = AI_PASSIVE; // use my IP
+
+    if ((rv = getaddrinfo(NULL, MYPORT, &hints, &servinfo)) != 0) {
+        fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
+        return 1;
+    }
+
+    // loop through all the results and bind to the first we can
+    for(p = servinfo; p != NULL; p = p->ai_next) {
+        if ((sockfd = socket(p->ai_family, p->ai_socktype,
+                p->ai_protocol)) == -1) {
+            perror("listener: socket");
+            continue;
+        }
+
+        if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
+            close(sockfd);
+            perror("listener: bind");
+            continue;
+        }
+
+        break;
+    }
+
+    if (p == NULL) {
+        fprintf(stderr, "listener: failed to bind socket\n");
+        return 2;
+    }
+
+    freeaddrinfo(servinfo);
+
+
+    addr_len = sizeof their_addr;
+    if ((numbytes = recvfrom(sockfd, buf, MAXBUFLEN-1 , 0,
+        (struct sockaddr *)&their_addr, &addr_len)) == -1) {
+        perror("recvfrom");
+        exit(1);
+    }
+
+    buf[numbytes] = '\0';
+    printf("%s\n", buf);
+
+    close(sockfd);
+
+    return 0;
+}