int sockbind(char *host, char *serv, int prot, int type)
{
- struct addrinfo hint, *addr;
+ struct addrinfo hint, *addr, *save;
int res;
int sock;
- /* initialize hint structure */
+ char buf[INET6_ADDRSTRLEN];
memset(&hint, 0, sizeof(struct addrinfo));
- hint.ai_flags = AI_PASSIVE; /* address for binding */
- hint.ai_family = PF_UNSPEC; /* generic address (IPv4 or IPv6) */
- hint.ai_protocol = prot; /* protocol */
- hint.ai_socktype = type; /* socket type */
+ hint.ai_flags = AI_PASSIVE; /* address for binding */
+ hint.ai_family = PF_UNSPEC; /* generic address (IPv4 or IPv6) */
+ hint.ai_protocol = prot; /* protocol */
+ hint.ai_socktype = type; /* socket type */
res = getaddrinfo(host, serv, &hint, &addr); /* calling getaddrinfo */
if (res != 0) { /* on error exit */
- printf("sockbind cannot resolve host %s, service %s, ", host, serv);
- printf("protocol %d: %s\n", prot, gai_strerror(res));
+ fprintf(stderr, "sockbind: resolution failed:");
+ fprintf(stderr, " %s\n", gai_strerror(res));
+ errno = 0; /* clear errno */
return -1;
}
- /* get a socket */
- sock = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
- if (sock < 0) {
- printf("sockconn cannot create socket\n");
- return sock;
+ save = addr; /* saving for freeaddrinfo */
+ while (addr != NULL) { /* loop on possible addresses */
+ sock = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
+ if (sock < 0) { /* on error */
+ if (addr->ai_next != NULL) { /* if other addresses */
+ addr=addr->ai_next; /* take next */
+ continue; /* restart cycle */
+ } else { /* else stop */
+ perror("sockbind: cannot create socket");
+ return sock;
+ }
+ }
+ if ( (res = bind(sock, addr->ai_addr, addr->ai_addrlen)) < 0) {
+ if (addr->ai_next != NULL) { /* if other addresses */
+ addr=addr->ai_next; /* take next */
+ close(sock); /* close socket */
+ continue; /* restart cycle */
+ } else { /* else stop */
+ perror("sockbind: cannot connect");
+ close(sock);
+ return res;
+ }
+ } else break; /* ok, we are binded! */
}
- /* connect the socket */
- res = bind(sock, addr->ai_addr, addr->ai_addrlen);
- if (res < 0) {
- printf("sockconn cannot bind socket\n");
- return res;
- }
- freeaddrinfo(addr); /* done, release memory */
+ freeaddrinfo(save); /* done, release memory */
return sock;
}