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connect: treat an interface bindlocal() problem as a non-fatal error

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I am using curl_easy_setopt(CURLOPT_INTERFACE, "if!something") to force
transfers to use a particular interface but the transfer fails with
CURLE_INTERFACE_FAILED, "Failed binding local connection end" if the
interface I specify has no IPv6 address. The cause is as follows:

The remote hostname resolves successfully and has an IPv6 address and an
IPv4 address.

cURL attempts to connect to the IPv6 address first.

bindlocal (in lib/connect.c) fails because Curl_if2ip cannot find an
IPv6 address on the interface.

This is a fatal error in singleipconnect()

This change will make cURL try the next IP address in the list.

Also included are two changes related to IPv6 address scope:

- Filter the choice of address in Curl_if2ip to only consider addresses
with the same scope ID as the connection address (mismatched scope for
local and remote address does not result in a working connection).

- bindlocal was ignoring the scope ID of addresses returned by
Curl_if2ip . Now it uses them.

Bug: http://curl.haxx.se/bug/view.cgi?id=1189
This commit is contained in:
Kim Vandry 2013-04-03 16:06:51 -04:00 committed by Daniel Stenberg
parent a181e7b084
commit 090b55c100
4 changed files with 145 additions and 79 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

105
lib/connect.c
View File

@ -310,41 +310,54 @@ static CURLcode bindlocal(struct connectdata *conn,
}
/* interface */
if(!is_host && (is_interface || Curl_if_is_interface_name(dev))) {
if(Curl_if2ip(af, dev, myhost, sizeof(myhost)) == NULL)
return CURLE_INTERFACE_FAILED;
/*
* We now have the numerical IP address in the 'myhost' buffer
*/
infof(data, "Local Interface %s is ip %s using address family %i\n",
dev, myhost, af);
done = 1;
if(!is_host) {
switch(Curl_if2ip(af, conn->scope, dev, myhost, sizeof(myhost))) {
case IF2IP_NOT_FOUND:
if(is_interface) {
/* Do not fall back to treating it as a host name */
failf(data, "Couldn't bind to interface '%s'", dev);
return CURLE_INTERFACE_FAILED;
}
break;
case IF2IP_AF_NOT_SUPPORTED:
/* Signal the caller to try another address family if available */
return CURLE_UNSUPPORTED_PROTOCOL;
case IF2IP_FOUND:
is_interface = TRUE;
/*
* We now have the numerical IP address in the 'myhost' buffer
*/
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 */
}
/* 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;
}
}
else {
if(!is_interface) {
/*
* This was not an interface, resolve the name as a host name
* or IP number
@ -388,11 +401,26 @@ static CURLcode bindlocal(struct connectdata *conn,
if(done > 0) {
#ifdef ENABLE_IPV6
/* ipv6 address */
if((af == AF_INET6) &&
(Curl_inet_pton(AF_INET6, myhost, &si6->sin6_addr) > 0)) {
si6->sin6_family = AF_INET6;
si6->sin6_port = htons(port);
sizeof_sa = sizeof(struct sockaddr_in6);
if(af == AF_INET6) {
#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
char *scope_ptr = strchr(myhost, '%');
if(scope_ptr) *(scope_ptr++) = 0;
#endif
if(Curl_inet_pton(AF_INET6, myhost, &si6->sin6_addr) > 0) {
si6->sin6_family = AF_INET6;
si6->sin6_port = htons(port);
#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
if(scope_ptr) {
/* The "myhost" string either comes from Curl_if2ip or
from Curl_printable_address. The latter returns only
numeric scope IDs and the former returns none at all.
So the scope ID, if present, is known to be numeric */
si6->sin6_scope_id = atoi(scope_ptr);
}
}
#endif
sizeof_sa = sizeof(struct sockaddr_in6);
}
else
#endif
@ -966,6 +994,11 @@ singleipconnect(struct connectdata *conn,
res = bindlocal(conn, sockfd, addr.family);
if(res) {
Curl_closesocket(conn, sockfd); /* close socket and bail out */
if(res == CURLE_UNSUPPORTED_PROTOCOL) {
/* The address family is not supported on this interface.
We can continue trying addresses */
return CURLE_OK;
}
return res;
}

17
lib/ftp.c
View File

@ -1066,12 +1066,17 @@ static CURLcode ftp_state_use_port(struct connectdata *conn,
if(*addr != '\0') {
/* attempt to get the address of the given interface name */
if(!Curl_if2ip(conn->ip_addr->ai_family, addr,
hbuf, sizeof(hbuf)))
/* not an interface, use the given string as host name instead */
host = addr;
else
host = hbuf; /* use the hbuf for host name */
switch(Curl_if2ip(conn->ip_addr->ai_family, conn->scope, addr,
hbuf, sizeof(hbuf))) {
case IF2IP_NOT_FOUND:
/* not an interface, use the given string as host name instead */
host = addr;
break;
case IF2IP_AF_NOT_SUPPORTED:
return CURLE_FTP_PORT_FAILED;
case IF2IP_FOUND:
host = hbuf; /* use the hbuf for host name */
}
}
else
/* there was only a port(-range) given, default the host */

92
lib/if2ip.c
View File

@ -83,42 +83,59 @@ bool Curl_if_is_interface_name(const char *interf)
return result;
}
char *Curl_if2ip(int af, const char *interf, char *buf, int buf_size)
if2ip_result_t Curl_if2ip(int af, unsigned int remote_scope,
const char *interf, char *buf, int buf_size)
{
struct ifaddrs *iface, *head;
char *ip = NULL;
if2ip_result_t res = IF2IP_NOT_FOUND;
if(getifaddrs(&head) >= 0) {
for(iface=head; iface != NULL; iface=iface->ifa_next) {
if((iface->ifa_addr != NULL) &&
(iface->ifa_addr->sa_family == af) &&
curl_strequal(iface->ifa_name, interf)) {
void *addr;
char scope[12]="";
char ipstr[64];
if(iface->ifa_addr != NULL) {
if(iface->ifa_addr->sa_family == af) {
if(curl_strequal(iface->ifa_name, interf)) {
void *addr;
char *ip;
char scope[12]="";
char ipstr[64];
#ifdef ENABLE_IPV6
if(af == AF_INET6) {
unsigned int scopeid = 0;
addr = &((struct sockaddr_in6 *)iface->ifa_addr)->sin6_addr;
if(af == AF_INET6) {
unsigned int scopeid = 0;
addr = &((struct sockaddr_in6 *)iface->ifa_addr)->sin6_addr;
#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
/* Include the scope of this interface as part of the address */
scopeid = ((struct sockaddr_in6 *)iface->ifa_addr)->sin6_scope_id;
/* Include the scope of this interface as part of the address */
scopeid =
((struct sockaddr_in6 *)iface->ifa_addr)->sin6_scope_id;
#endif
if(scopeid)
snprintf(scope, sizeof(scope), "%%%u", scopeid);
if(scopeid != remote_scope) {
/* We are interested only in interface addresses whose
scope ID matches the remote address we want to
connect to: global (0) for global, link-local for
link-local, etc... */
if(res == IF2IP_NOT_FOUND) res = IF2IP_AF_NOT_SUPPORTED;
continue;
}
if(scopeid)
snprintf(scope, sizeof(scope), "%%%u", scopeid);
}
else
#endif
addr = &((struct sockaddr_in *)iface->ifa_addr)->sin_addr;
res = IF2IP_FOUND;
ip = (char *) Curl_inet_ntop(af, addr, ipstr, sizeof(ipstr));
snprintf(buf, buf_size, "%s%s", ip, scope);
break;
}
}
else if((res == IF2IP_NOT_FOUND) &&
curl_strequal(iface->ifa_name, interf)) {
res = IF2IP_AF_NOT_SUPPORTED;
}
else
#endif
addr = &((struct sockaddr_in *)iface->ifa_addr)->sin_addr;
ip = (char *) Curl_inet_ntop(af, addr, ipstr, sizeof(ipstr));
snprintf(buf, buf_size, "%s%s", ip, scope);
ip = buf;
break;
}
}
freeifaddrs(head);
}
return ip;
return res;
}
#elif defined(HAVE_IOCTL_SIOCGIFADDR)
@ -128,30 +145,29 @@ bool Curl_if_is_interface_name(const char *interf)
/* This is here just to support the old interfaces */
char buf[256];
char *ip = Curl_if2ip(AF_INET, interf, buf, sizeof(buf));
return (ip != NULL) ? TRUE : FALSE;
return (Curl_if2ip(AF_INET, 0, interf, buf, sizeof(buf)) ==
IF2IP_NOT_FOUND) ? FALSE : TRUE;
}
char *Curl_if2ip(int af, const char *interf, char *buf, int buf_size)
if2ip_result_t Curl_if2ip(int af, unsigned int remote_scope,
const char *interf, char *buf, int buf_size)
{
struct ifreq req;
struct in_addr in;
struct sockaddr_in *s;
curl_socket_t dummy;
size_t len;
char *ip;
if(!interf || (af != AF_INET))
return NULL;
return IF2IP_NOT_FOUND;
len = strlen(interf);
if(len >= sizeof(req.ifr_name))
return NULL;
return IF2IP_NOT_FOUND;
dummy = socket(AF_INET, SOCK_STREAM, 0);
if(CURL_SOCKET_BAD == dummy)
return NULL;
return IF2IP_NOT_FOUND;
memset(&req, 0, sizeof(req));
memcpy(req.ifr_name, interf, len+1);
@ -159,15 +175,18 @@ char *Curl_if2ip(int af, const char *interf, char *buf, int buf_size)
if(ioctl(dummy, SIOCGIFADDR, &req) < 0) {
sclose(dummy);
return NULL;
/* With SIOCGIFADDR, we cannot tell the difference between an interface
that does not exist and an interface that has no address of the
correct family. Assume the interface does not exist */
return IF2IP_NOT_FOUND;
}
s = (struct sockaddr_in *)&req.ifr_addr;
memcpy(&in, &s->sin_addr, sizeof(in));
ip = (char *) Curl_inet_ntop(s->sin_family, &in, buf, buf_size);
Curl_inet_ntop(s->sin_family, &in, buf, buf_size);
sclose(dummy);
return ip;
return IF2IP_FOUND;
}
#else
@ -179,13 +198,14 @@ bool Curl_if_is_interface_name(const char *interf)
return FALSE;
}
char *Curl_if2ip(int af, const char *interf, char *buf, int buf_size)
if2ip_result_t Curl_if2ip(int af, unsigned int remote_scope,
const char *interf, char *buf, int buf_size)
{
(void) af;
(void) interf;
(void) buf;
(void) buf_size;
return NULL;
return IF2IP_NOT_FOUND;
}
#endif

10
lib/if2ip.h
View File

@ -24,7 +24,15 @@
#include "curl_setup.h"
bool Curl_if_is_interface_name(const char *interf);
char *Curl_if2ip(int af, const char *interf, char *buf, int buf_size);
typedef enum {
IF2IP_NOT_FOUND = 0, /* Interface not found */
IF2IP_AF_NOT_SUPPORTED = 1, /* Int. exists but has no address for this af */
IF2IP_FOUND = 2 /* The address has been stored in "buf" */
} if2ip_result_t;
if2ip_result_t Curl_if2ip(int af, unsigned int remote_scope,
const char *interf, char *buf, int buf_size);
#ifdef __INTERIX