icmp: add helpers to recognize ICMP error packets
Add two helper functions, one for IPv4 and one for IPv6, to recognize
the ICMP packets which are error responses.
This packets are special because they have as payload the original
header of the packet which generated it (RFC 792 says at least 8 bytes,
but Linux actually includes much more than that).
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/icmp.h b/include/linux/icmp.h
index 2d8aaf7..81ca84c 100644
--- a/include/linux/icmp.h
+++ b/include/linux/icmp.h
@@ -20,4 +20,19 @@ static inline struct icmphdr *icmp_hdr(const struct sk_buff *skb)
{
return (struct icmphdr *)skb_transport_header(skb);
}
+
+static inline bool icmp_is_err(int type)
+{
+ switch (type) {
+ case ICMP_DEST_UNREACH:
+ case ICMP_SOURCE_QUENCH:
+ case ICMP_REDIRECT:
+ case ICMP_TIME_EXCEEDED:
+ case ICMP_PARAMETERPROB:
+ return true;
+ }
+
+ return false;
+}
+
#endif /* _LINUX_ICMP_H */