From 96681723232e9eb0182279086fef291283004806 Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Wed, 27 May 2020 19:27:51 +0200

Subject: [PATCH] socket-util: add generic socket_pass_pktinfo() helper

The helper turns on the protocol specific "packet info" structure cmsg

for three relevant protocols we know.

(cherry picked from commit 35a3eb9bdc95d1e6ba25bc65c78959ea104e45a1)

Related: #1887181

---

 src/basic/socket-util.c | 23 +++++++++++++++++++++++

 src/basic/socket-util.h |  2 ++

 2 files changed, 25 insertions(+)

diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c

index 986bc6e67f..053bcba670 100644

--- a/src/basic/socket-util.c

+++ b/src/basic/socket-util.c

@@ -1246,3 +1246,26 @@ int socket_ioctl_fd(void) {

         return fd;

 }

+

+int socket_pass_pktinfo(int fd, bool b) {

+        int af;

+        socklen_t sl = sizeof(af);

+

+        if (getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &af, &sl) < 0)

+                return -errno;

+

+        switch (af) {

+

+        case AF_INET:

+                return setsockopt_int(fd, IPPROTO_IP, IP_PKTINFO, b);

+

+        case AF_INET6:

+                return setsockopt_int(fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, b);

+

+        case AF_NETLINK:

+                return setsockopt_int(fd, SOL_NETLINK, NETLINK_PKTINFO, b);

+

+        default:

+                return -EAFNOSUPPORT;

+        }

+}

diff --git a/src/basic/socket-util.h b/src/basic/socket-util.h

index 616f2e0d05..c7c9ad34d6 100644

--- a/src/basic/socket-util.h

+++ b/src/basic/socket-util.h

@@ -190,3 +190,5 @@ static inline int setsockopt_int(int fd, int level, int optname, int value) {

         return 0;

 }

+

+int socket_pass_pktinfo(int fd, bool b);