/*
* Find a server address that can be used by `caller' to contact
* the local service specified by `serv_uaddr'. If `clnt_uaddr' is
* non-NULL, it is used instead of `caller' as a hint suggesting
* the best address (e.g. the `r_addr' field of an rpc, which
* contains the rpcbind server address that the caller used).
*
* Returns the best server address as a malloc'd "universal address"
* string which should be freed by the caller. On error, returns NULL.
*/
char *
addrmerge(arpc_addr_t *caller, const char *serv_uaddr, const char *clnt_uaddr,
const char *netid)
{
struct ifaddrs *ifap, *ifp = NULL, *bestif;
arpc_addr_t *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
struct sockaddr_storage ss;
socklen_t len;
const char *hint_uaddr = NULL;
char *caller_uaddr = NULL;
char *ret = NULL;
int err;
#ifdef ND_DEBUG
if (debugging)
fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
#endif
caller_sa = (struct sockaddr *)caller->buf;
err = ar_taddr2uaddr(rpcbind_ioctx, netid, caller, &caller_uaddr);
if (err != 0) {
goto freeit;
}
/*
* Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
* address family is different from that of the caller.
*/
hint_sa = NULL;
if (clnt_uaddr != NULL) {
hint_uaddr = clnt_uaddr;
err = ar_uaddr2taddr(rpcbind_ioctx, netid,
clnt_uaddr, &hint_nbp);
if (err != 0) {
goto freeit;
}
hint_sa = (struct sockaddr *)hint_nbp->buf;
}
if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
hint_uaddr = caller_uaddr;
hint_sa = (struct sockaddr *)caller->buf;
}
#ifdef ND_DEBUG
if (debugging) {
fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
}
#endif
/* Local caller, just return the server address. */
if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
ret = strdup(serv_uaddr);
goto freeit;
}
if (getifaddrs(&ifp) < 0) {
goto freeit;
}
/*
* Loop through all interfaces. For each interface, see if the
* network portion of its address is equal to that of the client.
* If so, we have found the interface that we want to use.
*/
bestif = NULL;
for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
ifsa = ifap->ifa_addr;
ifmasksa = ifap->ifa_netmask;
if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
!(ifap->ifa_flags & IFF_UP)) {
continue;
}
switch (hint_sa->sa_family) {
case AF_INET:
/*
* If the hint address matches this interface
* address/netmask, then we're done.
*/
if (!bitmaskcmp(&SA2SINADDR(ifsa),
&SA2SINADDR(hint_sa), &SA2SINADDR(ifmasksa),
sizeof(struct in_addr))) {
bestif = ifap;
goto found;
}
break;
case AF_INET6:
/*
* For v6 link local addresses, if the caller is on
* a link-local address then use the scope id to see
* which one.
*/
in6_fillscopeid(SA2SIN6(ifsa));
if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
if (SA2SIN6(ifsa)->sin6_scope_id ==
SA2SIN6(caller_sa)->sin6_scope_id) {
bestif = ifap;
goto found;
}
} else if (!bitmaskcmp(&SA2SIN6ADDR(ifsa),
&SA2SIN6ADDR(hint_sa), &SA2SIN6ADDR(ifmasksa),
sizeof(struct in6_addr))) {
bestif = ifap;
goto found;
}
break;
default:
continue;
}
/*
* Remember the first possibly useful interface, preferring
* "normal" to point-to-point and loopback ones.
*/
if (bestif == NULL ||
(!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) &&
(bestif->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT)))) {
bestif = ifap;
}
}
if (bestif == NULL) {
goto freeit;
}
found:
/*
* Construct the new address using the the address from
* `bestif', and the port number from `serv_uaddr'.
*/
err = ar_uaddr2taddr(rpcbind_ioctx, netid, serv_uaddr, &serv_nbp);
if (err != 0) {
goto freeit;
}
serv_sa = (struct sockaddr *)serv_nbp->buf;
switch (ss.ss_family) {
case AF_INET:
len = sizeof(struct sockaddr_in);
memcpy(&ss, bestif->ifa_addr, len);
SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
break;
case AF_INET6:
len = sizeof(struct sockaddr_in6);
memcpy(&ss, bestif->ifa_addr, len);
SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
break;
default:
memset(&ss, 0, sizeof(ss));
len = 0;
break;
}
tbuf.len = len;
tbuf.maxlen = sizeof(ss);
tbuf.buf = (char *)&ss;
err = ar_taddr2uaddr(rpcbind_ioctx, netid, &tbuf, &ret);
if (err != 0) {
ret = NULL;
}
freeit:
if (caller_uaddr != NULL) {
free(caller_uaddr);
}
if (hint_nbp != NULL) {
if (hint_nbp->buf) {
free(hint_nbp->buf);
}
free(hint_nbp);
}
if (serv_nbp != NULL) {
if (serv_nbp->buf) {
free(serv_nbp->buf);
}
free(serv_nbp);
}
if (ifp != NULL) {
freeifaddrs(ifp);
}
#ifdef ND_DEBUG
if (debugging) {
fprintf(stderr, "addrmerge: returning %s\n", ret);
}
#endif
return ret;
}
/*
* Find a server address that can be used by `caller' to contact
* the local service specified by `serv_uaddr'. If `clnt_uaddr' is
* non-NULL, it is used instead of `caller' as a hint suggesting
* the best address (e.g. the `r_addr' field of an rpc, which
* contains the rpcbind server address that the caller used).
*
* Returns the best server address as a malloc'd "universal address"
* string which should be freed by the caller. On error, returns NULL.
*/
char *
addrmerge(struct netbuf *caller, const char *serv_uaddr, const char *clnt_uaddr,
const char *netid)
{
struct ifaddrs *ifap, *ifp = NULL, *bestif;
struct netbuf *serv_nbp = NULL, *hint_nbp = NULL, tbuf;
struct sockaddr *caller_sa, *hint_sa, *ifsa, *ifmasksa, *serv_sa;
struct sockaddr_storage ss;
struct netconfig *nconf;
char *caller_uaddr = NULL;
const char *hint_uaddr = NULL;
char *ret = NULL;
int bestif_goodness;
#ifdef ND_DEBUG
if (debugging)
fprintf(stderr, "addrmerge(caller, %s, %s, %s\n", serv_uaddr,
clnt_uaddr == NULL ? "NULL" : clnt_uaddr, netid);
#endif
caller_sa = caller->buf;
if ((nconf = rpcbind_get_conf(netid)) == NULL)
goto freeit;
if ((caller_uaddr = taddr2uaddr(nconf, caller)) == NULL)
goto freeit;
/*
* Use `clnt_uaddr' as the hint if non-NULL, but ignore it if its
* address family is different from that of the caller.
*/
hint_sa = NULL;
if (clnt_uaddr != NULL) {
hint_uaddr = clnt_uaddr;
if ((hint_nbp = uaddr2taddr(nconf, clnt_uaddr)) == NULL)
goto freeit;
hint_sa = hint_nbp->buf;
}
if (hint_sa == NULL || hint_sa->sa_family != caller_sa->sa_family) {
hint_uaddr = caller_uaddr;
hint_sa = caller->buf;
}
#ifdef ND_DEBUG
if (debugging)
fprintf(stderr, "addrmerge: hint %s\n", hint_uaddr);
#endif
/* Local caller, just return the server address. */
if (strncmp(caller_uaddr, "0.0.0.0.", 8) == 0 ||
strncmp(caller_uaddr, "::.", 3) == 0 || caller_uaddr[0] == '/') {
ret = strdup(serv_uaddr);
goto freeit;
}
if (getifaddrs(&ifp) < 0)
goto freeit;
/*
* Loop through all interface addresses. We are listening to an address
* if any of the following are true:
* a) It's a loopback address
* b) It was specified with the -h command line option
* c) There were no -h command line options.
*
* Among addresses on which we are listening, choose in order of
* preference an address that is:
*
* a) Equal to the hint
* b) A link local address with the same scope ID as the client's
* address, if the client's address is also link local
* c) An address on the same subnet as the client's address
* d) A non-localhost, non-p2p address
* e) Any usable address
*/
bestif = NULL;
bestif_goodness = 0;
for (ifap = ifp; ifap != NULL; ifap = ifap->ifa_next) {
ifsa = ifap->ifa_addr;
ifmasksa = ifap->ifa_netmask;
/* Skip addresses where we don't listen */
if (ifsa == NULL || ifsa->sa_family != hint_sa->sa_family ||
!(ifap->ifa_flags & IFF_UP))
continue;
if (!(ifap->ifa_flags & IFF_LOOPBACK) && !listen_addr(ifsa))
continue;
if ((hint_sa->sa_family == AF_INET) &&
((((struct sockaddr_in*)hint_sa)->sin_addr.s_addr ==
((struct sockaddr_in*)ifsa)->sin_addr.s_addr))) {
const int goodness = 4;
bestif_goodness = goodness;
bestif = ifap;
goto found;
}
#ifdef INET6
if ((hint_sa->sa_family == AF_INET6) &&
(0 == memcmp(&((struct sockaddr_in6*)hint_sa)->sin6_addr,
&((struct sockaddr_in6*)ifsa)->sin6_addr,
sizeof(struct in6_addr))) &&
(((struct sockaddr_in6*)hint_sa)->sin6_scope_id ==
(((struct sockaddr_in6*)ifsa)->sin6_scope_id))) {
const int goodness = 4;
bestif_goodness = goodness;
bestif = ifap;
goto found;
}
if (hint_sa->sa_family == AF_INET6) {
/*
* For v6 link local addresses, if the caller is on
* a link-local address then use the scope id to see
* which one.
*/
if (IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(ifsa)) &&
IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(caller_sa)) &&
IN6_IS_ADDR_LINKLOCAL(&SA2SIN6ADDR(hint_sa))) {
if (SA2SIN6(ifsa)->sin6_scope_id ==
SA2SIN6(caller_sa)->sin6_scope_id) {
const int goodness = 3;
if (bestif_goodness < goodness) {
bestif = ifap;
bestif_goodness = goodness;
}
}
}
}
#endif /* INET6 */
if (0 == bitmaskcmp(hint_sa, ifsa, ifmasksa)) {
const int goodness = 2;
if (bestif_goodness < goodness) {
bestif = ifap;
bestif_goodness = goodness;
}
}
if (!(ifap->ifa_flags & (IFF_LOOPBACK | IFF_POINTOPOINT))) {
const int goodness = 1;
if (bestif_goodness < goodness) {
bestif = ifap;
bestif_goodness = goodness;
}
}
if (bestif == NULL)
bestif = ifap;
}
if (bestif == NULL)
goto freeit;
found:
/*
* Construct the new address using the address from
* `bestif', and the port number from `serv_uaddr'.
*/
serv_nbp = uaddr2taddr(nconf, serv_uaddr);
if (serv_nbp == NULL)
goto freeit;
serv_sa = serv_nbp->buf;
memcpy(&ss, bestif->ifa_addr, bestif->ifa_addr->sa_len);
switch (ss.ss_family) {
case AF_INET:
SA2SIN(&ss)->sin_port = SA2SIN(serv_sa)->sin_port;
break;
#ifdef INET6
case AF_INET6:
SA2SIN6(&ss)->sin6_port = SA2SIN6(serv_sa)->sin6_port;
break;
#endif
}
tbuf.len = ss.ss_len;
tbuf.maxlen = sizeof(ss);
tbuf.buf = &ss;
ret = taddr2uaddr(nconf, &tbuf);
freeit:
if (caller_uaddr != NULL)
free(caller_uaddr);
if (hint_nbp != NULL) {
free(hint_nbp->buf);
free(hint_nbp);
}
if (serv_nbp != NULL) {
free(serv_nbp->buf);
free(serv_nbp);
}
if (ifp != NULL)
freeifaddrs(ifp);
#ifdef ND_DEBUG
if (debugging)
fprintf(stderr, "addrmerge: returning %s\n", ret);
#endif
return ret;
}
