Added files for the scanning, have not integrated them fully.

git-svn-id: https://subversion.cs.uiuc.edu/svn/bang/eoh2009@98 69d76c3e-0761-0410-948c-9895a8bb34fc

src/base/bang-scan.c

@@ -0,0 +1,195 @@
+/**
+ * \file bang-scan.c
+ */
+
+/*
+ * listener.c -- a datagram sockets "server" demo
+ * using code from beej's guide
+ */
+
+#include"bang-scan.h"
+#include"bang-signals.h"
+#include"bang-types.h"
+#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 BRDCSTPORT "4950"
+#define HNDSHKPORT "4951"
+
+#define MAXBUFLEN 100
+
+// get sockaddr, IPv4 or IPv6:
+static 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);
+}
+
+static int bang_acknowledge(const char *reply_ip) {
+	int sockfd;
+	struct addrinfo hints, *servinfo, *p;
+	int rv;
+	int numbytes;
+
+	memset(&hints, 0, sizeof hints);
+	hints.ai_family = AF_UNSPEC;
+	hints.ai_socktype = SOCK_DGRAM;
+
+	if ((rv = getaddrinfo(reply_ip, HNDSHKPORT, &hints, &servinfo)) != 0) {
+		fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
+		return 1;
+	}
+
+	// loop through all the results and make a socket
+	for(p = servinfo; p != NULL; p = p->ai_next) {
+		if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) {
+			perror("socket");
+			continue;
+		}
+
+		break;
+	}
+
+	if (p == NULL) {
+		fprintf(stderr, "failed to bind socket\n");
+		return 2;
+	}
+
+	if ((numbytes = sendto(sockfd, "BANG.", strlen("BANG."), 0,
+					p->ai_addr, p->ai_addrlen)) == -1) {
+		perror("sendto");
+		exit(1);
+	}
+
+	freeaddrinfo(servinfo);
+
+	printf("Acknowledged new user (%s)\n", reply_ip);
+	close(sockfd);
+
+	return 0;
+
+}
+
+int listen_for_announce_thread() {
+	int sockfd;
+	struct addrinfo hints, *servinfo, *p;
+	int rv;
+	int numbytes;
+	struct sockaddr_storage their_addr;
+	char buf[MAXBUFLEN];
+	size_t addr_len;
+	char s[INET6_ADDRSTRLEN];
+
+	memset(&hints, 0, sizeof hints);
+	hints.ai_family = AF_UNSPEC;
+	hints.ai_socktype = SOCK_DGRAM;
+	hints.ai_flags = AI_PASSIVE; // use my IP
+
+	if ((rv = getaddrinfo(NULL, BRDCSTPORT, &hints, &servinfo)) == -1) {
+		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("socket");
+			continue;
+		}
+
+		if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
+			close(sockfd);
+			perror("bind");
+			continue;
+		}
+
+		break;
+	}
+
+	if (p == NULL) {
+		fprintf(stderr, "failed to bind socket\n");
+		return 2;
+	}
+
+	freeaddrinfo(servinfo);
+
+	printf("Listening for new clients...\n");
+
+	addr_len = sizeof their_addr;
+	if ((numbytes = recvfrom(sockfd, buf, MAXBUFLEN-1 , 0,
+					(struct sockaddr *)&their_addr, &addr_len)) == -1) {
+		perror("recvfrom");
+		exit(1);
+	}
+
+	printf("New user (%s)\n",
+			inet_ntop(their_addr.ss_family,
+				get_in_addr((struct sockaddr *)&their_addr),
+				s, sizeof s));
+	buf[numbytes] = '\0';
+	printf("packet contains \"%s\"\n", buf);
+
+	close(sockfd);
+
+	if (strcmp(buf, "BANG?") == 0)
+		bang_acknowledge(inet_ntop(their_addr.ss_family, get_in_addr((struct sockaddr *)&their_addr), s, sizeof s));
+	else if (strcmp(buf, "BANG.") == 0)
+		printf("Setting up connection with new user.\n");
+
+	return 0;
+
+}
+
+int BANG_announce() {
+	int sockfd;
+	struct sockaddr_in their_addr; /*  connector's address information */
+	struct hostent *he;
+	int numbytes;
+	int broadcast = 1;
+
+	if ((he=gethostbyname("255.255.255.255")) == NULL) {  /* TODO: Use get addrinfo. */
+		herror("gethostbyname");
+		exit(1);
+	}
+
+	if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
+		perror("socket");
+		exit(1);
+	}
+
+	// this call is the difference between this program and talker.c:
+	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(atoi(BRDCSTPORT)); // 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, "BANG?", strlen("BANG?"), 0,
+					(struct sockaddr *)&their_addr, sizeof their_addr)) == -1) {
+		perror("sendto");
+		exit(1);
+	}
+
+	printf("Broadcasting my existence to LAN...\n", numbytes, inet_ntoa(their_addr.sin_addr));
+
+	close(sockfd);
+
+	return 0;
+
+}

src/base/bang-scan.h

@@ -0,0 +1,18 @@
+#ifndef __BANG_SCAN_H
+#define __BAN_SCAN_H
+
+void BANG_listen();
+
+int BANG_announce();
+
+/**
+ * \param to_accept Whether or not the library will try to
+ * immediately connect to a peer.
+ *
+ * If true, the bang library will try to automatically try to
+ * connect to any new peers.
+ *
+ * default: true
+ */
+void BANG_set_acceptance(char to_accept);
+#endif