Introduce TTL in QuicReceivedPacket.

net/tools/quic/quic_socket_utils.cc

Index: net/tools/quic/quic_socket_utils.cc
diff --git a/net/tools/quic/quic_socket_utils.cc b/net/tools/quic/quic_socket_utils.cc
index 327d95606fdf1f21b3808915e588cb1038e3a2f8..a6bc4c0c49642dee758371de8087ab35a7dee866 100644
--- a/net/tools/quic/quic_socket_utils.cc
+++ b/net/tools/quic/quic_socket_utils.cc
@@ -73,6 +73,23 @@ bool QuicSocketUtils::GetOverflowFromMsghdr(struct msghdr* hdr,
 }
 
 // static
+bool QuicSocketUtils::GetTtlFromMsghdr(struct msghdr* hdr, int* ttl) {
+  if (hdr->msg_controllen > 0) {
+    struct cmsghdr* cmsg;
+    for (cmsg = CMSG_FIRSTHDR(hdr); cmsg != nullptr;
+         cmsg = CMSG_NXTHDR(hdr, cmsg)) {
+      if ((cmsg->cmsg_level == IPPROTO_IP && cmsg->cmsg_type == IP_TTL) ||
+          (cmsg->cmsg_level == IPPROTO_IPV6 &&
+           cmsg->cmsg_type == IPV6_HOPLIMIT)) {
+        *ttl = *(reinterpret_cast<int*>(CMSG_DATA(cmsg)));
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+// static
 int QuicSocketUtils::SetGetAddressInfo(int fd, int address_family) {
   int get_local_ip = 1;
   int rc = setsockopt(fd, IPPROTO_IP, IP_PKTINFO, &get_local_ip,