This fix, originally sent to XFRM/IPsec, has been recommended by
Steffen Klassert to submit to the net tree, since it changes ICMP
behavior.

The patch addresses a minor issue related to the IPv4 source address
of ICMP error messages. The bug only occurs when xfrm policies are
configured. It originated from an old 2011 commit:

commit 415b3334a21a ("icmp: Fix regression in nexthop resolution during
replies.")

Submitting to net-next with a selftest.

Antony Antony (2):
  icmp: fix ICMP error source address when xfrm policy matches
  selftests: net: add ICMP error source address test over xfrm tunnel

 net/ipv4/icmp.c                           |   1 -
 tools/testing/selftests/net/Makefile      |   1 +
 tools/testing/selftests/net/xfrm_state.sh | 578 ++++++++++++++++++++++
 3 files changed, 579 insertions(+), 1 deletion(-)
 create mode 100755 tools/testing/selftests/net/xfrm_state.sh

---
v1->v2 : add kernel selftest script
v2->v3 : fix test script.
v3->v4 : fix test script based on reviews
     - clarify commit message
     - Changed subsystem prefix to icmp: since fix is in net/ipv4/icmp.c

-antony