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--interface: add support for Linux VRF

The --interface command (CURLOPT_INTERFACE option) already uses
SO_BINDTODEVICE on Linux, but it tries to parse it as an interface or IP
address first, which fails in case the user passes a VRF.

Try to use the socket option immediately and parse it as a fallback
instead.  Update the documentation to mention this feature, and that it
requires the binary to be ran by root or with CAP_NET_RAW capabilities
for this to work.

Closes #2024
This commit is contained in:
Luca Boccassi 2017-10-26 19:42:55 +01:00 committed by Daniel Stenberg
parent b78dce2526
commit 32828cc4fb
No known key found for this signature in database
GPG Key ID: 5CC908FDB71E12C2
2 changed files with 32 additions and 24 deletions

View File

@ -10,3 +10,7 @@ name, IP address or host name. An example could look like:
curl --interface eth0:1 https://www.example.com/
If this option is used several times, the last one will be used.
On Linux it can be used to specify a VRF, but the binary needs to either
have CAP_NET_RAW or to be ran as root. More information about Linux VRF:
https://www.kernel.org/doc/Documentation/networking/vrf.txt

View File

@ -285,6 +285,34 @@ static CURLcode bindlocal(struct connectdata *conn,
/* interface */
if(!is_host) {
#ifdef SO_BINDTODEVICE
/* I am not sure any other OSs than Linux that provide this feature,
* and at the least I cannot test. --Ben
*
* This feature allows one to tightly bind the local socket to a
* particular interface. This will force even requests to other
* local interfaces to go out the external interface.
*
*
* Only bind to the interface when specified as interface, not just
* as a hostname or ip address.
*
* interface might be a VRF, eg: vrf-blue, which means it cannot be
* converted to an IP address and would fail Curl_if2ip. Simply try
* to use it straight away.
*/
if(setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE,
dev, (curl_socklen_t)strlen(dev) + 1) == 0) {
/* This is typically "errno 1, error: Operation not permitted" if
* you're not running as root or another suitable privileged
* user.
* If it succeeds it means the parameter was a valid interface and
* not an IP address. Return immediately.
*/
return CURLE_OK;
}
#endif
switch(Curl_if2ip(af, scope, conn->scope_id, dev,
myhost, sizeof(myhost))) {
case IF2IP_NOT_FOUND:
@ -305,30 +333,6 @@ static CURLcode bindlocal(struct connectdata *conn,
infof(data, "Local Interface %s is ip %s using address family %i\n",
dev, myhost, af);
done = 1;
#ifdef SO_BINDTODEVICE
/* I am not sure any other OSs than Linux that provide this feature,
* and at the least I cannot test. --Ben
*
* This feature allows one to tightly bind the local socket to a
* particular interface. This will force even requests to other
* local interfaces to go out the external interface.
*
*
* Only bind to the interface when specified as interface, not just
* as a hostname or ip address.
*/
if(setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE,
dev, (curl_socklen_t)strlen(dev) + 1) != 0) {
error = SOCKERRNO;
infof(data, "SO_BINDTODEVICE %s failed with errno %d: %s;"
" will do regular bind\n",
dev, error, Curl_strerror(conn, error));
/* This is typically "errno 1, error: Operation not permitted" if
you're not running as root or another suitable privileged
user */
}
#endif
break;
}
}