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* net: remove unneeded switch fall-throughLi RongQing2019-02-211-1/+0
| | | | | | | | This case block has been terminated by a return, so not need a switch fall-through Signed-off-by: Li RongQing <lirongqing@baidu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* bridge: Snoop Multicast Router AdvertisementsLinus Lüssing2019-01-221-1/+4
| | | | | | | | | | | | | | | | | | | When multiple multicast routers are present in a broadcast domain then only one of them will be detectable via IGMP/MLD query snooping. The multicast router with the lowest IP address will become the selected and active querier while all other multicast routers will then refrain from sending queries. To detect such rather silent multicast routers, too, RFC4286 ("Multicast Router Discovery") provides a standardized protocol to detect multicast routers for multicast snooping switches. This patch implements the necessary MRD Advertisement message parsing and after successful processing adds such routers to the internal multicast router list. Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>
* bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() internalsLinus Lüssing2019-01-221-32/+30
| | | | | | | | | | | | | With this patch the internal use of the skb_trimmed is reduced to the ICMPv6/IGMP checksum verification. And for the length checks the newly introduced helper functions are used instead of calculating and checking with skb->len directly. These changes should hopefully make it easier to verify that length checks are performed properly. Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>
* bridge: simplify ip_mc_check_igmp() and ipv6_mc_check_mld() callsLinus Lüssing2019-01-221-20/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* net: fix wrong skb_get() usage / crash in IGMP/MLD parsing codeLinus Lüssing2015-08-131-15/+18
| | | | | | | | | | | | | | | | | | | | | | | The recent refactoring of the IGMP and MLD parsing code into ipv6_mc_check_mld() / ip_mc_check_igmp() introduced a potential crash / BUG() invocation for bridges: I wrongly assumed that skb_get() could be used as a simple reference counter for an skb which is not the case. skb_get() bears additional semantics, a user count. This leads to a BUG() invocation in pskb_expand_head() / kernel panic if pskb_may_pull() is called on an skb with a user count greater than one - unfortunately the refactoring did just that. Fixing this by removing the skb_get() call and changing the API: The caller of ipv6_mc_check_mld() / ip_mc_check_igmp() now needs to additionally check whether the returned skb_trimmed is a clone. Fixes: 9afd85c9e455 ("net: Export IGMP/MLD message validation code") Reported-by: Brenden Blanco <bblanco@plumgrid.com> Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: fix two sparse warnings introduced by IGMP/MLD parsing exportsLinus Lüssing2015-05-041-1/+1
| | | | | | | | | | | | > net/core/skbuff.c:4108:13: sparse: incorrect type in assignment (different base types) > net/ipv6/mcast_snoop.c:63 ipv6_mc_check_exthdrs() warn: unsigned 'offset' is never less than zero. Introduced by 9afd85c9e4552b276e2f4cfefd622bdeeffbbf26 ("net: Export IGMP/MLD message validation code") Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>
* net: Export IGMP/MLD message validation codeLinus Lüssing2015-05-041-0/+213
With this patch, the IGMP and MLD message validation functions are moved from the bridge code to IPv4/IPv6 multicast files. Some small refactoring was done to enhance readibility and to iron out some differences in behaviour between the IGMP and MLD parsing code (e.g. the skb-cloning of MLD messages is now only done if necessary, just like the IGMP part always did). Finally, these IGMP and MLD message validation functions are exported so that not only the bridge can use it but batman-adv later, too. Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: David S. Miller <davem@davemloft.net>