iputils/0007-ping-allow-user-to-specify-VRF-and-source-IP.patch

From 2cc34ea408602f84fe102598ca258126531736c9 Mon Sep 17 00:00:00 2001
From: Jon Harrison <jon.harrison@metaswitch.com>
Date: Tue, 9 Jul 2019 16:48:07 +0100
Subject: [PATCH] ping: allow user to specify VRF and source IP
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Without this, the options for sending a ping in the context of a VRF are
limited.

We can send a ping with a specific source IP address.  For example:

  ping 10.1.1.3 -I 10.1.1.2

We can send a ping in the context of a Linux VRF.  For example:

  ping 10.1.1.3 -I vrf_red

However, when pinging in the context of a VRF, Linux does not always choose
a sensible source IP address – the source IP might not belong to the VRF.
As a result, the ping won’t get a response.  As a result, we want to be able
to specify both a VRF and a source IP address when initiating a ping.  For
example:

  ping 10.1.1.3 -I vrf_red -I 10.1.1.2

Ping reads in the command line parameters fine and sets up the 'source' and
'device' variables, but currently ignores the device if the source IP
address is non-zero.  This commit adds a branch to ping.c that does the
socket bind to the device even in the case where the source IP is non-zero.
This branch is based on the existing case where source IP is zero, but
simplified a bit because we've already got a source IP address to use.

(cherry picked from commit 9e08707d743b29e853df81bd7def1729e3afe55d)
---
 doc/ping.xml | 15 ++++++++++-----
 ping.c       | 44 +++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/doc/ping.xml b/doc/ping.xml
index bdf07b3..034e40c 100644
--- a/doc/ping.xml
+++ b/doc/ping.xml
@@ -158,11 +158,16 @@ to values less than 0.2 seconds.</para>
   <varlistentry>
   <term><option>-I </option><emphasis remap='I'>interface</emphasis></term>
   <listitem>
-<para><emphasis remap='I'>interface</emphasis> is either an address, or an interface name.
-If <emphasis remap='I'>interface</emphasis> is an address, it sets source address
-to specified interface address.
-If <emphasis remap='I'>interface</emphasis> in an interface name, it sets
-source interface to specified interface.
+<para><emphasis remap='I'>interface</emphasis> is either an
+address, an interface name or a VRF name. If
+<emphasis remap="I">interface</emphasis> is an address, it
+sets source address to specified interface address. If
+<emphasis remap="I">interface</emphasis> is an interface
+name, it sets source interface to specified interface.
+If <emphasis remap="I">interface</emphasis> is a VRF
+name, each packet is routed using the corresponding
+routing table; in this case, the <option>-I</option> option
+can be repeated to specify a source address.
 NOTE: For IPv6, when doing ping to a link-local scope
 address, link specification (by the '%'-notation in
 <emphasis remap='I'>destination</emphasis>, or by this option)
diff --git a/ping.c b/ping.c
index c870390..0f87723 100644
--- a/ping.c
+++ b/ping.c
@@ -705,7 +705,43 @@ int ping4_run(int argc, char **argv, struct addrinfo *ai, socket_st *sock)
 		}
 #endif
 		close(probe_fd);
-	} while (0);
+
+	} else if (device) {
+		struct sockaddr_in dst = whereto;
+		struct ifreq ifr;
+		int fd = sock->fd;
+		int rc;
+		int errno_save;
+
+		memset(&ifr, 0, sizeof(ifr));
+		strncpy(ifr.ifr_name, device, IFNAMSIZ - 1);
+
+		enable_capability_raw();
+		rc = setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, device, strlen(device) + 1);
+		errno_save = errno;
+		disable_capability_raw();
+
+		if (rc == -1) {
+			if (IN_MULTICAST(ntohl(dst.sin_addr.s_addr))) {
+				struct ip_mreqn imr;
+
+				if (ioctl(fd, SIOCGIFINDEX, &ifr) < 0) {
+					fprintf(stderr, "ping: %s: %s\n", "(\"unknown interface\")", device);
+					exit(2);
+				}
+				memset(&imr, 0, sizeof(imr));
+				imr.imr_ifindex = ifr.ifr_ifindex;
+				if (setsockopt(fd, SOL_IP, IP_MULTICAST_IF,
+					       &imr, sizeof(imr)) == -1) {
+					fprintf(stderr, "ping: IP_MULTICAST_IF: %s\n", strerror(errno));
+					exit(2);
+				}
+			} else {
+				fprintf(stderr, "ping: SO_BINDTODEVICE %s: %s\n", device, strerror(errno_save));
+				exit(2);
+			}
+		}
+	}
 
 	if (whereto.sin_addr.s_addr == 0)
 		whereto.sin_addr.s_addr = source.sin_addr.s_addr;
@@ -957,8 +993,10 @@ int ping4_receive_error_msg(socket_st *sock)
 						  (1 << ICMP_REDIRECT) |
 						  (1 << ICMP_ECHOREPLY));
 			if (setsockopt(sock->fd, SOL_RAW, ICMP_FILTER, (const void *)&filt,
-						   sizeof(filt)) == -1)
-				error(2, errno, "setsockopt(ICMP_FILTER)");
+						   sizeof(filt)) == -1) {
+				fprintf(stderr, "ping: setsockopt(ICMP_FILTER): %s\n", strerror(errno));
+				exit(2);
+			}
 		}
 		net_errors++;
 		nerrors++;
-- 
2.40.1