alistair23-linux/include/linux/ip.h
Linus Lüssing ba5ea61462 bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() calls
This patch refactors ip_mc_check_igmp(), ipv6_mc_check_mld() and
their callers (more precisely, the Linux bridge) to not rely on
the skb_trimmed parameter anymore.

An skb with its tail trimmed to the IP packet length was initially
introduced for the following three reasons:

1) To be able to verify the ICMPv6 checksum.
2) To be able to distinguish the version of an IGMP or MLD query.
   They are distinguishable only by their size.
3) To avoid parsing data for an IGMPv3 or MLDv2 report that is
   beyond the IP packet but still within the skb.

The first case still uses a cloned and potentially trimmed skb to
verfiy. However, there is no need to propagate it to the caller.
For the second and third case explicit IP packet length checks were
added.

This hopefully makes ip_mc_check_igmp() and ipv6_mc_check_mld() easier
to read and verfiy, as well as easier to use.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-22 17:18:08 -08:00

43 lines
1.2 KiB
C

/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Definitions for the IP protocol.
*
* Version: @(#)ip.h 1.0.2 04/28/93
*
* Authors: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _LINUX_IP_H
#define _LINUX_IP_H
#include <linux/skbuff.h>
#include <uapi/linux/ip.h>
static inline struct iphdr *ip_hdr(const struct sk_buff *skb)
{
return (struct iphdr *)skb_network_header(skb);
}
static inline struct iphdr *inner_ip_hdr(const struct sk_buff *skb)
{
return (struct iphdr *)skb_inner_network_header(skb);
}
static inline struct iphdr *ipip_hdr(const struct sk_buff *skb)
{
return (struct iphdr *)skb_transport_header(skb);
}
static inline unsigned int ip_transport_len(const struct sk_buff *skb)
{
return ntohs(ip_hdr(skb)->tot_len) - skb_network_header_len(skb);
}
#endif /* _LINUX_IP_H */