Fix ICMPv4 EchoReply packet checksum

The checksum was not being reset before being re-calculated and sent out.
This caused the sent checksum to always be `0x0800`.

Fixes #605.

PiperOrigin-RevId: 260965059

1 files changed, 2 insertions, 3 deletions

diff --git a/test/syscalls/linux/raw_socket_icmp.cc b/test/syscalls/linux/raw_socket_icmp.cc
index ad19120d5..1c07bacc2 100644
--- a/test/syscalls/linux/raw_socket_icmp.cc
+++ b/test/syscalls/linux/raw_socket_icmp.cc
@@ -470,9 +470,8 @@ void RawSocketICMPTest::ExpectICMPSuccess(const struct icmphdr& icmp) {
         EXPECT_EQ(recvd_icmp->un.echo.id, icmp.un.echo.id);
         // A couple are different.
         EXPECT_EQ(recvd_icmp->type, ICMP_ECHOREPLY);
-        // The checksum is computed in such a way that it is guaranteed to have
-        // changed.
-        EXPECT_NE(recvd_icmp->checksum, icmp.checksum);
+        // The checksum computed over the reply should still be valid.
+        EXPECT_EQ(Checksum(recvd_icmp), 0);
         break;
     }
   }