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osmo_sock_init2: improve support for AF_UNSPEC 

osmo_sock_init2 abstract two calls of getaddrinfo into one.
While there aren't problems with AF_INET or AF_INET6. When using
AF_UNSPEC there are corner cases when this fails. E.g. calling
local_host with "" and remote_host with an IPv6 only address results in
setting up a local socket with AF_INET while trying to connect from there towards
AF_INET6 will most likely fail.
To prevent such cases with AF_UNSPEC, search prio calling any syscalls if local and remote site
supports AF_INET or AF_INET6. In case both supported, prefer AF_INET6

Change-Id: I397c633931fd00d4f083955a3c49a40fb002d766
This commit is contained in:
Alexander Couzens 2020-06-03 00:28:02 +02:00 committed by laforge
parent 6300aff3b2
commit 2c962f5de1
4 changed files with 105 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

92
src/socket.c
View File

@ -260,22 +260,85 @@ int osmo_sock_init2(uint16_t family, uint16_t type, uint8_t proto,
const char *local_host, uint16_t local_port,
const char *remote_host, uint16_t remote_port, unsigned int flags)
{
struct addrinfo *result, *rp;
struct addrinfo *local = NULL, *remote = NULL, *rp;
int sfd = -1, rc, on = 1;
bool local_ipv4 = false, local_ipv6 = false;
bool remote_ipv4 = false, remote_ipv6 = false;
if ((flags & (OSMO_SOCK_F_BIND | OSMO_SOCK_F_CONNECT)) == 0) {
LOGP(DLGLOBAL, LOGL_ERROR, "invalid: you have to specify either "
"BIND or CONNECT flags\n");
return -EINVAL;
}
/* figure out local address infos */
if (flags & OSMO_SOCK_F_BIND) {
local = addrinfo_helper(family, type, proto, local_host, local_port, true);
if (!local)
return -EINVAL;
}
/* figure out remote address infos */
if (flags & OSMO_SOCK_F_CONNECT) {
remote = addrinfo_helper(family, type, proto, remote_host, remote_port, false);
if (!remote) {
if (local)
freeaddrinfo(local);
return -EINVAL;
}
}
/* It must do a full run to ensure AF_UNSPEC does not fail.
* In case first local valid entry is IPv4 and only remote valid entry
* is IPv6 or vice versa */
if (family == AF_UNSPEC) {
for (rp = local; rp != NULL; rp = rp->ai_next) {
switch (rp->ai_family) {
case AF_INET:
local_ipv4 = true;
break;
case AF_INET6:
local_ipv6 = true;
break;
}
}
for (rp = remote; rp != NULL; rp = rp->ai_next) {
switch (rp->ai_family) {
case AF_INET:
remote_ipv4 = true;
break;
case AF_INET6:
remote_ipv6 = true;
break;
}
}
/* priotize ipv6 as per RFC */
if (local_ipv6 && remote_ipv6)
family = AF_INET6;
else if (local_ipv4 && remote_ipv4)
family = AF_INET;
else {
if (local)
freeaddrinfo(local);
if (remote)
freeaddrinfo(remote);
LOGP(DLGLOBAL, LOGL_ERROR, "Unable to find a common protocol (IPv4 or IPv6) for local host: %s and remote host: %s.\n",
local_host, remote_host);
return -ENODEV;
}
}
/* figure out local side of socket */
if (flags & OSMO_SOCK_F_BIND) {
result = addrinfo_helper(family, type, proto, local_host, local_port, true);
if (!result)
return -EINVAL;
for (rp = local; rp != NULL; rp = rp->ai_next) {
/* When called with AF_UNSPEC, family will set to IPv4 or IPv6 */
if (rp->ai_family != family)
continue;
for (rp = result; rp != NULL; rp = rp->ai_next) {
sfd = socket_helper(rp, flags);
if (sfd < 0)
continue;
@ -302,8 +365,11 @@ int osmo_sock_init2(uint16_t family, uint16_t type, uint8_t proto,
}
break;
}
freeaddrinfo(result);
freeaddrinfo(local);
if (rp == NULL) {
if (remote)
freeaddrinfo(remote);
LOGP(DLGLOBAL, LOGL_ERROR, "no suitable local addr found for: %s:%u\n",
local_host, local_port);
return -ENODEV;
@ -316,14 +382,11 @@ int osmo_sock_init2(uint16_t family, uint16_t type, uint8_t proto,
/* figure out remote side of socket */
if (flags & OSMO_SOCK_F_CONNECT) {
result = addrinfo_helper(family, type, proto, remote_host, remote_port, false);
if (!result) {
if (sfd >= 0)
close(sfd);
return -EINVAL;
}
for (rp = remote; rp != NULL; rp = rp->ai_next) {
/* When called with AF_UNSPEC, family will set to IPv4 or IPv6 */
if (rp->ai_family != family)
continue;
for (rp = result; rp != NULL; rp = rp->ai_next) {
if (sfd < 0) {
sfd = socket_helper(rp, flags);
if (sfd < 0)
@ -343,7 +406,8 @@ int osmo_sock_init2(uint16_t family, uint16_t type, uint8_t proto,
}
break;
}
freeaddrinfo(result);
freeaddrinfo(remote);
if (rp == NULL) {
LOGP(DLGLOBAL, LOGL_ERROR, "no suitable remote addr found for: %s:%u\n",
remote_host, remote_port);

21
tests/socket/socket_test.c
View File

@ -120,6 +120,27 @@ static int test_sockinit2(void)
* FreeBSD 10 or 11 VM at home */
OSMO_ASSERT(!strncmp(name, "(r=127.0.0.1:53<->l=127.0.0.1", 29));
#endif
printf("Checking osmo_sock_init2(AF_UNSPEC) must fail on mixed IPv4 & IPv6\n");
fd = osmo_sock_init2(AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "127.0.0.1", 0, "::1", 53,
OSMO_SOCK_F_BIND|OSMO_SOCK_F_CONNECT);
OSMO_ASSERT(fd < 0);
printf("Checking osmo_sock_init2(AF_UNSPEC) must fail on mixed IPv6 & IPv4\n");
fd = osmo_sock_init2(AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "::1", 0, "127.0.0.1", 53,
OSMO_SOCK_F_BIND|OSMO_SOCK_F_CONNECT);
OSMO_ASSERT(fd < 0);
printf("Checking osmo_sock_init2(AF_UNSPEC) BIND + CONNECT on IPv4\n");
fd = osmo_sock_init2(AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "127.0.0.1", 0, "127.0.0.1", 53,
OSMO_SOCK_F_BIND|OSMO_SOCK_F_CONNECT);
OSMO_ASSERT(fd >= 0);
printf("Checking osmo_sock_init2(AF_UNSPEC) BIND + CONNECT on IPv6\n");
fd = osmo_sock_init2(AF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "::1", 0, "::1", 53,
OSMO_SOCK_F_BIND|OSMO_SOCK_F_CONNECT);
OSMO_ASSERT(fd >= 0);
talloc_free(name);
return 0;

2
tests/socket/socket_test.err
View File

@ -1,2 +1,4 @@
invalid: both bind and connect flags set: 0.0.0.0:0
invalid: you have to specify either BIND or CONNECT flags
Unable to find a common protocol (IPv4 or IPv6) for local host: 127.0.0.1 and remote host: ::1.
Unable to find a common protocol (IPv4 or IPv6) for local host: ::1 and remote host: 127.0.0.1.

4
tests/socket/socket_test.ok
View File

@ -5,3 +5,7 @@ Checking osmo_sock_init2() with bind to a random local UDP port
Checking osmo_sock_init2() for OSMO_SOCK_F_NONBLOCK
Checking osmo_sock_init2() for invalid flags
Checking osmo_sock_init2() for combined BIND + CONNECT
Checking osmo_sock_init2(AF_UNSPEC) must fail on mixed IPv4 & IPv6
Checking osmo_sock_init2(AF_UNSPEC) must fail on mixed IPv6 & IPv4
Checking osmo_sock_init2(AF_UNSPEC) BIND + CONNECT on IPv4
Checking osmo_sock_init2(AF_UNSPEC) BIND + CONNECT on IPv6