hush/libbb/xconnect.c
Denis Vlasenko 5c51a7ca52 nc: make connecting to IPv4 from IPv6-enabled hosts easier
(was requiring -s <local addr>)
2007-06-05 20:08:11 +00:00

353 lines
8.8 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Connect to host at port using address resolution from getaddrinfo
*
*/
#include <netinet/in.h>
#include "libbb.h"
int setsockopt_reuseaddr(int fd)
{
return setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &const_int_1, sizeof(const_int_1));
}
int setsockopt_broadcast(int fd)
{
return setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &const_int_1, sizeof(const_int_1));
}
void xconnect(int s, const struct sockaddr *s_addr, socklen_t addrlen)
{
if (connect(s, s_addr, addrlen) < 0) {
if (ENABLE_FEATURE_CLEAN_UP)
close(s);
if (s_addr->sa_family == AF_INET)
bb_perror_msg_and_die("%s (%s)",
"cannot connect to remote host",
inet_ntoa(((struct sockaddr_in *)s_addr)->sin_addr));
bb_perror_msg_and_die("cannot connect to remote host");
}
}
/* Return port number for a service.
* If "port" is a number use it as the port.
* If "port" is a name it is looked up in /etc/services, if it isnt found return
* default_port */
unsigned bb_lookup_port(const char *port, const char *protocol, unsigned default_port)
{
unsigned port_nr = default_port;
if (port) {
int old_errno;
/* Since this is a lib function, we're not allowed to reset errno to 0.
* Doing so could break an app that is deferring checking of errno. */
old_errno = errno;
port_nr = bb_strtou(port, NULL, 10);
if (errno || port_nr > 65535) {
struct servent *tserv = getservbyname(port, protocol);
port_nr = default_port;
if (tserv)
port_nr = ntohs(tserv->s_port);
}
errno = old_errno;
}
return (uint16_t)port_nr;
}
/* "Old" networking API - only IPv4 */
/*
void bb_lookup_host(struct sockaddr_in *s_in, const char *host)
{
struct hostent *he;
memset(s_in, 0, sizeof(struct sockaddr_in));
s_in->sin_family = AF_INET;
he = xgethostbyname(host);
memcpy(&(s_in->sin_addr), he->h_addr_list[0], he->h_length);
}
int xconnect_tcp_v4(struct sockaddr_in *s_addr)
{
int s = xsocket(AF_INET, SOCK_STREAM, 0);
xconnect(s, (struct sockaddr*) s_addr, sizeof(*s_addr));
return s;
}
*/
/* "New" networking API */
int get_nport(const struct sockaddr *sa)
{
#if ENABLE_FEATURE_IPV6
if (sa->sa_family == AF_INET6) {
return ((struct sockaddr_in6*)sa)->sin6_port;
}
#endif
if (sa->sa_family == AF_INET) {
return ((struct sockaddr_in*)sa)->sin_port;
}
/* What? UNIX socket? IPX?? :) */
return -1;
}
void set_nport(len_and_sockaddr *lsa, unsigned port)
{
#if ENABLE_FEATURE_IPV6
if (lsa->sa.sa_family == AF_INET6) {
lsa->sin6.sin6_port = port;
return;
}
#endif
if (lsa->sa.sa_family == AF_INET) {
lsa->sin.sin_port = port;
return;
}
/* What? UNIX socket? IPX?? :) */
}
/* We hijack this constant to mean something else */
/* It doesn't hurt because we will remove this bit anyway */
#define DIE_ON_ERROR AI_CANONNAME
/* host: "1.2.3.4[:port]", "www.google.com[:port]"
* port: if neither of above specifies port # */
static len_and_sockaddr* str2sockaddr(
const char *host, int port,
USE_FEATURE_IPV6(sa_family_t af,)
int ai_flags)
{
int rc;
len_and_sockaddr *r = NULL;
struct addrinfo *result = NULL;
const char *org_host = host; /* only for error msg */
const char *cp;
struct addrinfo hint;
/* Ugly parsing of host:addr */
if (ENABLE_FEATURE_IPV6 && host[0] == '[') {
host++;
cp = strchr(host, ']');
if (!cp || cp[1] != ':') /* Malformed: must have [xx]:nn */
bb_error_msg_and_die("bad address '%s'", org_host);
//return r; /* return NULL */
} else {
cp = strrchr(host, ':');
if (ENABLE_FEATURE_IPV6 && cp && strchr(host, ':') != cp) {
/* There is more than one ':' (e.g. "::1") */
cp = NULL; /* it's not a port spec */
}
}
if (cp) {
int sz = cp - host + 1;
host = safe_strncpy(alloca(sz), host, sz);
if (ENABLE_FEATURE_IPV6 && *cp != ':')
cp++; /* skip ']' */
cp++; /* skip ':' */
port = xatou16(cp);
}
memset(&hint, 0 , sizeof(hint));
#if !ENABLE_FEATURE_IPV6
hint.ai_family = AF_INET; /* do not try to find IPv6 */
#else
hint.ai_family = af;
#endif
/* Needed. Or else we will get each address thrice (or more)
* for each possible socket type (tcp,udp,raw...): */
hint.ai_socktype = SOCK_STREAM;
hint.ai_flags = ai_flags & ~DIE_ON_ERROR;
rc = getaddrinfo(host, NULL, &hint, &result);
if (rc || !result) {
bb_error_msg("bad address '%s'", org_host);
if (ai_flags & DIE_ON_ERROR)
xfunc_die();
goto ret;
}
r = xmalloc(offsetof(len_and_sockaddr, sa) + result->ai_addrlen);
r->len = result->ai_addrlen;
memcpy(&r->sa, result->ai_addr, result->ai_addrlen);
set_nport(r, htons(port));
ret:
freeaddrinfo(result);
return r;
}
#if !ENABLE_FEATURE_IPV6
#define str2sockaddr(host, port, af, ai_flags) str2sockaddr(host, port, ai_flags)
#endif
#if ENABLE_FEATURE_IPV6
len_and_sockaddr* host_and_af2sockaddr(const char *host, int port, sa_family_t af)
{
return str2sockaddr(host, port, af, 0);
}
len_and_sockaddr* xhost_and_af2sockaddr(const char *host, int port, sa_family_t af)
{
return str2sockaddr(host, port, af, DIE_ON_ERROR);
}
#endif
len_and_sockaddr* host2sockaddr(const char *host, int port)
{
return str2sockaddr(host, port, AF_UNSPEC, 0);
}
len_and_sockaddr* xhost2sockaddr(const char *host, int port)
{
return str2sockaddr(host, port, AF_UNSPEC, DIE_ON_ERROR);
}
len_and_sockaddr* xdotted2sockaddr(const char *host, int port)
{
return str2sockaddr(host, port, AF_UNSPEC, AI_NUMERICHOST | DIE_ON_ERROR);
}
int xsocket_type(len_and_sockaddr **lsap, USE_FEATURE_IPV6(int family,) int sock_type)
{
SKIP_FEATURE_IPV6(enum { family = AF_INET };)
len_and_sockaddr *lsa;
int fd;
int len;
#if ENABLE_FEATURE_IPV6
if (family == AF_UNSPEC) {
fd = socket(AF_INET6, sock_type, 0);
if (fd >= 0) {
family = AF_INET6;
goto done;
}
family = AF_INET;
}
#endif
fd = xsocket(family, sock_type, 0);
len = sizeof(struct sockaddr_in);
#if ENABLE_FEATURE_IPV6
if (family == AF_INET6) {
done:
len = sizeof(struct sockaddr_in6);
}
#endif
lsa = xzalloc(offsetof(len_and_sockaddr, sa) + len);
lsa->len = len;
lsa->sa.sa_family = family;
*lsap = lsa;
return fd;
}
int xsocket_stream(len_and_sockaddr **lsap)
{
return xsocket_type(lsap, USE_FEATURE_IPV6(AF_UNSPEC,) SOCK_STREAM);
}
static int create_and_bind_or_die(const char *bindaddr, int port, int sock_type)
{
int fd;
len_and_sockaddr *lsa;
if (bindaddr && bindaddr[0]) {
lsa = xdotted2sockaddr(bindaddr, port);
/* user specified bind addr dictates family */
fd = xsocket(lsa->sa.sa_family, sock_type, 0);
} else {
fd = xsocket_type(&lsa, USE_FEATURE_IPV6(AF_UNSPEC,) sock_type);
set_nport(lsa, htons(port));
}
setsockopt_reuseaddr(fd);
xbind(fd, &lsa->sa, lsa->len);
free(lsa);
return fd;
}
int create_and_bind_stream_or_die(const char *bindaddr, int port)
{
return create_and_bind_or_die(bindaddr, port, SOCK_STREAM);
}
int create_and_bind_dgram_or_die(const char *bindaddr, int port)
{
return create_and_bind_or_die(bindaddr, port, SOCK_DGRAM);
}
int create_and_connect_stream_or_die(const char *peer, int port)
{
int fd;
len_and_sockaddr *lsa;
lsa = xhost2sockaddr(peer, port);
fd = xsocket(lsa->sa.sa_family, SOCK_STREAM, 0);
setsockopt_reuseaddr(fd);
xconnect(fd, &lsa->sa, lsa->len);
free(lsa);
return fd;
}
int xconnect_stream(const len_and_sockaddr *lsa)
{
int fd = xsocket(lsa->sa.sa_family, SOCK_STREAM, 0);
xconnect(fd, &lsa->sa, lsa->len);
return fd;
}
/* We hijack this constant to mean something else */
/* It doesn't hurt because we will add this bit anyway */
#define IGNORE_PORT NI_NUMERICSERV
static char* sockaddr2str(const struct sockaddr *sa, socklen_t salen, int flags)
{
char host[128];
char serv[16];
int rc = getnameinfo(sa, salen,
host, sizeof(host),
/* can do ((flags & IGNORE_PORT) ? NULL : serv) but why bother? */
serv, sizeof(serv),
/* do not resolve port# into service _name_ */
flags | NI_NUMERICSERV
);
if (rc)
return NULL;
if (flags & IGNORE_PORT)
return xstrdup(host);
#if ENABLE_FEATURE_IPV6
if (sa->sa_family == AF_INET6) {
if (strchr(host, ':')) /* heh, it's not a resolved hostname */
return xasprintf("[%s]:%s", host, serv);
/*return xasprintf("%s:%s", host, serv);*/
/* - fall through instead */
}
#endif
/* For now we don't support anything else, so it has to be INET */
/*if (sa->sa_family == AF_INET)*/
return xasprintf("%s:%s", host, serv);
/*return xstrdup(host);*/
}
char* xmalloc_sockaddr2host(const struct sockaddr *sa, socklen_t salen)
{
return sockaddr2str(sa, salen, 0);
}
char* xmalloc_sockaddr2host_noport(const struct sockaddr *sa, socklen_t salen)
{
return sockaddr2str(sa, salen, IGNORE_PORT);
}
char* xmalloc_sockaddr2hostonly_noport(const struct sockaddr *sa, socklen_t salen)
{
return sockaddr2str(sa, salen, NI_NAMEREQD | IGNORE_PORT);
}
char* xmalloc_sockaddr2dotted(const struct sockaddr *sa, socklen_t salen)
{
return sockaddr2str(sa, salen, NI_NUMERICHOST);
}
char* xmalloc_sockaddr2dotted_noport(const struct sockaddr *sa, socklen_t salen)
{
return sockaddr2str(sa, salen, NI_NUMERICHOST | IGNORE_PORT);
}