IPv4 bind helpers. lf_listen_tcp returns a listening TCP socket. lf_bind_udp returns a bound UDP socket. You own accept, recv, send, and shutdown.

host == NULL binds INADDR_ANY. Port "0" lets the kernel pick an ephemeral port; use getsockname to read it back.

Functions

lf_listen_tcp

Creates an IPv4 TCP socket, binds it, and listens. Returns the fd, or -1 on error.

int lf_listen_tcp(const char *host, const char *port);

/* Usage */
int fd = lf_listen_tcp("127.0.0.1", "8080");
int client = accept(fd, NULL, NULL);
lf_close(client);
lf_close(fd);

lf_bind_udp

Creates an IPv4 UDP socket and binds it. Returns the fd, or -1 on error.

int lf_bind_udp(const char *host, const char *port);

lf_close

Closes fd if it is >= 0. Safe with -1.

void lf_close(int fd);

get_in_addr

Returns a pointer to the IPv4 or IPv6 address inside a struct sockaddr. Returns NULL if sa is NULL.

void *get_in_addr(struct sockaddr *sa);

/* Usage */
struct sockaddr_storage client_addr;
socklen_t client_addr_sz = sizeof(client_addr);
char buf[INET6_ADDRSTRLEN];
int new_fd = accept(fd, (struct sockaddr *)&client_addr, &client_addr_sz);
inet_ntop(client_addr.ss_family,
          get_in_addr((struct sockaddr *)&client_addr),
          buf, sizeof buf);