refactored notify.c for clarity

diff --git a/listen.c b/listen.c
index fd7ce87..79cff94 100644 (file)
--- a/listen.c
+++ b/listen.c
@@ -21,12 +21,13 @@ void sigchld_handler(int s)
        while(waitpid(-1, NULL, WNOHANG) > 0);
 }
 
-// look for an IPv4 host:port in an address structure
+// look for an IPv4/6 host:port in an address structure
 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)

diff --git a/notify.c b/notify.c
index 0f00e34..89e71e6 100644 (file)
--- a/notify.c
+++ b/notify.c
@@ -10,30 +10,28 @@
 
 #include <arpa/inet.h>
 
-#define PORT "3490" // the port client will be connecting to 
+#define PORT "3490"
+#define MAX_MSG_ACCEPT_BYTES 100
 
-#define MAXDATASIZE 100 // max number of bytes we can get at once 
-
-// get sockaddr, IPv4 or IPv6:
+// look for an IPv4/6 host:port in an address structure
 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(int argc, char *argv[])
 {
        int sockfd, numbytes;  
-       char buf[MAXDATASIZE];
-       struct addrinfo hints, *servinfo, *p;
-       int rv;
+       struct addrinfo hints, *servinfo, *port;
        char s[INET6_ADDRSTRLEN];
+       int rv;
+       char buf[MAX_MSG_ACCEPT_BYTES];
 
        if (argc != 3) {
-           fprintf(stderr,"usage: client hostname 'message'\n");
+           fprintf(stderr, "usage: client hostname 'message'\n");
            exit(1);
        }
 
@@ -41,29 +39,28 @@ int main(int argc, char *argv[])
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;
 
+    // look up local address information
        if ((rv = getaddrinfo(argv[1], PORT, &hints, &servinfo)) != 0) {
                fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
                return 1;
        }
 
-       // loop through all the results and connect 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) {
+       // loop over available interfaces and try to bind to port
+       for(port = servinfo; port != NULL; port = port->ai_next) {
+               if ((sockfd = socket(port->ai_family, port->ai_socktype,
+                               port->ai_protocol)) == -1) {
                        perror("client: socket");
                        continue;
                }
-
-               if (connect(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
+               if (connect(sockfd, port->ai_addr, port->ai_addrlen) == -1) {
                        close(sockfd);
                        perror("client: connect");
                        continue;
                }
-
                break;
        }
 
-       if (p == NULL) {
+       if (port == NULL) {
                fprintf(stderr, "client: failed to connect\n");
                return 2;
        }