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lib/socket: detect protocol in nl_socket_set_fd()

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With support for socket option SO_PROTOCOL we don't need the protocol
argument to nl_socket_set_fd(). Maybe we should drop the protocol argument
and just not support nl_socket_set_fd() on older systems. But instead
keep the argument and allow passing -1 to autodetect it.

If the user sets a protocol option, we check via getsockopt() that the
value is correct and error out otherwise.

On older kernels, the user must set the value. Otherwise
nl_socket_set_fd() will fail.

Signed-off-by: Thomas Haller <thaller@redhat.com>
This commit is contained in:
Thomas Haller 2015-03-06 12:33:49 +01:00
parent d62a68cda3
commit 24d333075a
1 changed files with 63 additions and 9 deletions
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72
lib/socket.c
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@ -29,6 +29,8 @@
#include "defs.h"
#include "sys/socket.h"
#include <netlink-private/netlink.h>
#include <netlink-private/socket.h>
#include <netlink/netlink.h>
@ -577,7 +579,12 @@ int nl_socket_get_fd(const struct nl_sock *sk)
* socket similar to nl_connect().
*
* @arg sk Netlink socket (required)
* @arg protocol Netlink protocol to use (required)
* @arg protocol The socket protocol (optional). Linux 2.6.32 supports
* the socket option SO_PROTOCOL. In this case, you can set
* protocol to a negative value and let it autodetect.
* If you set it to a non-negative value, the detected protocol
* must match the one provided.
* To support older kernels, you must specify the protocol.
* @arg fd Socket file descriptor to use (required)
*
* Set the socket file descriptor. @fd must be valid and bind'ed.
@ -592,7 +599,7 @@ int nl_socket_get_fd(const struct nl_sock *sk)
* possibly unusable.
*
* @retval -NLE_BAD_SOCK Netlink socket is already connected
* @retval -NLE_INVAL Socket is not connected
* @retval -NLE_INVAL Socket is of unexpected type
*/
int nl_socket_set_fd(struct nl_sock *sk, int protocol, int fd)
{
@ -600,6 +607,7 @@ int nl_socket_set_fd(struct nl_sock *sk, int protocol, int fd)
socklen_t addrlen;
char buf[64];
struct sockaddr_nl local = { 0 };
int so_type = -1, so_protocol = -1;
if (sk->s_fd != -1)
return -NLE_BAD_SOCK;
@ -610,16 +618,62 @@ int nl_socket_set_fd(struct nl_sock *sk, int protocol, int fd)
err = getsockname(fd, (struct sockaddr *) &local,
&addrlen);
if (err < 0) {
NL_DBG(4, "nl_socket_set_fd(%p): getsockname() failed with %d (%s)\n",
sk, errno, strerror_r(errno, buf, sizeof(buf)));
NL_DBG(4, "nl_socket_set_fd(%p,%d): getsockname() failed with %d (%s)\n",
sk, fd, errno, strerror_r(errno, buf, sizeof(buf)));
return -nl_syserr2nlerr(errno);
}
if (addrlen != sizeof(local))
return -NLE_NOADDR;
return -NLE_INVAL;
if (local.nl_family != AF_NETLINK) {
NL_DBG(4, "nl_socket_set_fd(%p,%d): getsockname() returned family %d instead of %d (AF_NETLINK)\n",
sk, fd, local.nl_family, AF_NETLINK);
return -NLE_INVAL;
}
if (local.nl_family != AF_NETLINK)
return -NLE_AF_NOSUPPORT;
addrlen = sizeof(so_type);
err = getsockopt(fd, SOL_SOCKET, SO_TYPE, &so_type, &addrlen);
if (err < 0) {
NL_DBG(4, "nl_socket_set_fd(%p,%d): getsockopt() for SO_TYPE failed with %d (%s)\n",
sk, fd, errno, strerror_r(errno, buf, sizeof(buf)));
return -nl_syserr2nlerr(errno);
}
if (addrlen != sizeof(so_type))
return -NLE_INVAL;
if (so_type != SOCK_RAW) {
NL_DBG(4, "nl_socket_set_fd(%p,%d): getsockopt() returned SO_TYPE %d instead of %d (SOCK_RAW)\n",
sk, fd, so_type, SOCK_RAW);
return -NLE_INVAL;
}
#if SO_PROTOCOL
addrlen = sizeof(so_protocol);
err = getsockopt(fd, SOL_SOCKET, SO_PROTOCOL, &so_protocol, &addrlen);
if (err < 0) {
if (errno == ENOPROTOOPT)
goto no_so_protocol;
NL_DBG(4, "nl_socket_set_fd(%p,%d): getsockopt() for SO_PROTOCOL failed with %d (%s)\n",
sk, fd, errno, strerror_r(errno, buf, sizeof(buf)));
return -nl_syserr2nlerr(errno);
}
if (addrlen != sizeof(so_protocol))
return -NLE_INVAL;
if (protocol >= 0 && protocol != so_protocol) {
NL_DBG(4, "nl_socket_set_fd(%p,%d): getsockopt() for SO_PROTOCOL returned %d instead of %d\n",
sk, fd, so_protocol, protocol);
return -NLE_INVAL;
}
if (0)
#endif
{
no_so_protocol:
if (protocol < 0) {
NL_DBG(4, "nl_socket_set_fd(%p,%d): unknown protocol and unable to detect it via SO_PROTOCOL socket option\n",
sk, fd);
return -NLE_INVAL;
}
so_protocol = protocol;
}
if (sk->s_local.nl_pid != local.nl_pid) {
/* the port id differs. The socket is using a port id not managed by
@ -629,7 +683,7 @@ int nl_socket_set_fd(struct nl_sock *sk, int protocol, int fd)
}
sk->s_local = local;
sk->s_fd = fd;
sk->s_proto = protocol;
sk->s_proto = so_protocol;
return 0;
}