Commit 29a1ff65 authored by David S. Miller's avatar David S. Miller

Merge branch 'igmp_mld_export'

Linus Lüssing says:

====================
Exporting IGMP/MLD checking from bridge code

The multicast optimizations in batman-adv are yet only usable and
enabled in non-bridged scenarios. To be able to support bridged setups
batman-adv needs to be able to detect IGMP/MLD queriers and reports on
mesh nodes without bridges, too. See the following link for details:

http://www.open-mesh.org/projects/batman-adv/wiki/Multicast-optimizations-listener-reports

To avoid duplicate code between the bridge and batman-adv, the IGMP/MLD
message validation code is moved from the bridge to the IPv4/IPv6 stack.

On the way, some refactoring to increase readability and to iron out
some subtle differences between the IGMP and MLD parsing code is done.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents c19ae86a 9afd85c9
......@@ -130,5 +130,6 @@ extern void ip_mc_unmap(struct in_device *);
extern void ip_mc_remap(struct in_device *);
extern void ip_mc_dec_group(struct in_device *in_dev, __be32 addr);
extern void ip_mc_inc_group(struct in_device *in_dev, __be32 addr);
int ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed);
#endif
......@@ -3419,6 +3419,9 @@ static inline void skb_checksum_none_assert(const struct sk_buff *skb)
bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
unsigned int transport_len,
__sum16(*skb_chkf)(struct sk_buff *skb));
u32 skb_get_poff(const struct sk_buff *skb);
u32 __skb_get_poff(const struct sk_buff *skb, void *data,
......
......@@ -142,6 +142,7 @@ void ipv6_mc_unmap(struct inet6_dev *idev);
void ipv6_mc_remap(struct inet6_dev *idev);
void ipv6_mc_init_dev(struct inet6_dev *idev);
void ipv6_mc_destroy_dev(struct inet6_dev *idev);
int ipv6_mc_check_mld(struct sk_buff *skb, struct sk_buff **skb_trimmed);
void addrconf_dad_failure(struct inet6_ifaddr *ifp);
bool ipv6_chk_mcast_addr(struct net_device *dev, const struct in6_addr *group,
......
......@@ -975,9 +975,6 @@ static int br_ip4_multicast_igmp3_report(struct net_bridge *br,
int err = 0;
__be32 group;
if (!pskb_may_pull(skb, sizeof(*ih)))
return -EINVAL;
ih = igmpv3_report_hdr(skb);
num = ntohs(ih->ngrec);
len = sizeof(*ih);
......@@ -1248,25 +1245,14 @@ static int br_ip4_multicast_query(struct net_bridge *br,
max_delay = 10 * HZ;
group = 0;
}
} else {
if (!pskb_may_pull(skb, sizeof(struct igmpv3_query))) {
err = -EINVAL;
goto out;
}
} else if (skb->len >= sizeof(*ih3)) {
ih3 = igmpv3_query_hdr(skb);
if (ih3->nsrcs)
goto out;
max_delay = ih3->code ?
IGMPV3_MRC(ih3->code) * (HZ / IGMP_TIMER_SCALE) : 1;
}
/* RFC2236+RFC3376 (IGMPv2+IGMPv3) require the multicast link layer
* all-systems destination addresses (224.0.0.1) for general queries
*/
if (!group && iph->daddr != htonl(INADDR_ALLHOSTS_GROUP)) {
err = -EINVAL;
} else {
goto out;
}
......@@ -1329,12 +1315,6 @@ static int br_ip6_multicast_query(struct net_bridge *br,
(port && port->state == BR_STATE_DISABLED))
goto out;
/* RFC2710+RFC3810 (MLDv1+MLDv2) require link-local source addresses */
if (!(ipv6_addr_type(&ip6h->saddr) & IPV6_ADDR_LINKLOCAL)) {
err = -EINVAL;
goto out;
}
if (skb->len == sizeof(*mld)) {
if (!pskb_may_pull(skb, sizeof(*mld))) {
err = -EINVAL;
......@@ -1358,14 +1338,6 @@ static int br_ip6_multicast_query(struct net_bridge *br,
is_general_query = group && ipv6_addr_any(group);
/* RFC2710+RFC3810 (MLDv1+MLDv2) require the multicast link layer
* all-nodes destination address (ff02::1) for general queries
*/
if (is_general_query && !ipv6_addr_is_ll_all_nodes(&ip6h->daddr)) {
err = -EINVAL;
goto out;
}
if (is_general_query) {
saddr.proto = htons(ETH_P_IPV6);
saddr.u.ip6 = ip6h->saddr;
......@@ -1557,74 +1529,22 @@ static int br_multicast_ipv4_rcv(struct net_bridge *br,
struct sk_buff *skb,
u16 vid)
{
struct sk_buff *skb2 = skb;
const struct iphdr *iph;
struct sk_buff *skb_trimmed = NULL;
struct igmphdr *ih;
unsigned int len;
unsigned int offset;
int err;
/* We treat OOM as packet loss for now. */
if (!pskb_may_pull(skb, sizeof(*iph)))
return -EINVAL;
iph = ip_hdr(skb);
if (iph->ihl < 5 || iph->version != 4)
return -EINVAL;
if (!pskb_may_pull(skb, ip_hdrlen(skb)))
return -EINVAL;
err = ip_mc_check_igmp(skb, &skb_trimmed);
iph = ip_hdr(skb);
if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
return -EINVAL;
if (iph->protocol != IPPROTO_IGMP) {
if (!ipv4_is_local_multicast(iph->daddr))
if (err == -ENOMSG) {
if (!ipv4_is_local_multicast(ip_hdr(skb)->daddr))
BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
return 0;
} else if (err < 0) {
return err;
}
len = ntohs(iph->tot_len);
if (skb->len < len || len < ip_hdrlen(skb))
return -EINVAL;
if (skb->len > len) {
skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
return -ENOMEM;
err = pskb_trim_rcsum(skb2, len);
if (err)
goto err_out;
}
len -= ip_hdrlen(skb2);
offset = skb_network_offset(skb2) + ip_hdrlen(skb2);
__skb_pull(skb2, offset);
skb_reset_transport_header(skb2);
err = -EINVAL;
if (!pskb_may_pull(skb2, sizeof(*ih)))
goto out;
switch (skb2->ip_summed) {
case CHECKSUM_COMPLETE:
if (!csum_fold(skb2->csum))
break;
/* fall through */
case CHECKSUM_NONE:
skb2->csum = 0;
if (skb_checksum_complete(skb2))
goto out;
}
err = 0;
BR_INPUT_SKB_CB(skb)->igmp = 1;
ih = igmp_hdr(skb2);
ih = igmp_hdr(skb);
switch (ih->type) {
case IGMP_HOST_MEMBERSHIP_REPORT:
......@@ -1633,21 +1553,19 @@ static int br_multicast_ipv4_rcv(struct net_bridge *br,
err = br_ip4_multicast_add_group(br, port, ih->group, vid);
break;
case IGMPV3_HOST_MEMBERSHIP_REPORT:
err = br_ip4_multicast_igmp3_report(br, port, skb2, vid);
err = br_ip4_multicast_igmp3_report(br, port, skb_trimmed, vid);
break;
case IGMP_HOST_MEMBERSHIP_QUERY:
err = br_ip4_multicast_query(br, port, skb2, vid);
err = br_ip4_multicast_query(br, port, skb_trimmed, vid);
break;
case IGMP_HOST_LEAVE_MESSAGE:
br_ip4_multicast_leave_group(br, port, ih->group, vid);
break;
}
out:
__skb_push(skb2, offset);
err_out:
if (skb2 != skb)
kfree_skb(skb2);
if (skb_trimmed)
kfree_skb(skb_trimmed);
return err;
}
......@@ -1657,138 +1575,42 @@ static int br_multicast_ipv6_rcv(struct net_bridge *br,
struct sk_buff *skb,
u16 vid)
{
struct sk_buff *skb2;
const struct ipv6hdr *ip6h;
u8 icmp6_type;
u8 nexthdr;
__be16 frag_off;
unsigned int len;
int offset;
struct sk_buff *skb_trimmed = NULL;
struct mld_msg *mld;
int err;
if (!pskb_may_pull(skb, sizeof(*ip6h)))
return -EINVAL;
ip6h = ipv6_hdr(skb);
err = ipv6_mc_check_mld(skb, &skb_trimmed);
/*
* We're interested in MLD messages only.
* - Version is 6
* - MLD has always Router Alert hop-by-hop option
* - But we do not support jumbrograms.
*/
if (ip6h->version != 6)
return 0;
/* Prevent flooding this packet if there is no listener present */
if (!ipv6_addr_is_ll_all_nodes(&ip6h->daddr))
if (err == -ENOMSG) {
if (!ipv6_addr_is_ll_all_nodes(&ipv6_hdr(skb)->daddr))
BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
if (ip6h->nexthdr != IPPROTO_HOPOPTS ||
ip6h->payload_len == 0)
return 0;
len = ntohs(ip6h->payload_len) + sizeof(*ip6h);
if (skb->len < len)
return -EINVAL;
nexthdr = ip6h->nexthdr;
offset = ipv6_skip_exthdr(skb, sizeof(*ip6h), &nexthdr, &frag_off);
if (offset < 0 || nexthdr != IPPROTO_ICMPV6)
return 0;
/* Okay, we found ICMPv6 header */
skb2 = skb_clone(skb, GFP_ATOMIC);
if (!skb2)
return -ENOMEM;
err = -EINVAL;
if (!pskb_may_pull(skb2, offset + sizeof(struct icmp6hdr)))
goto out;
len -= offset - skb_network_offset(skb2);
__skb_pull(skb2, offset);
skb_reset_transport_header(skb2);
skb_postpull_rcsum(skb2, skb_network_header(skb2),
skb_network_header_len(skb2));
icmp6_type = icmp6_hdr(skb2)->icmp6_type;
switch (icmp6_type) {
case ICMPV6_MGM_QUERY:
case ICMPV6_MGM_REPORT:
case ICMPV6_MGM_REDUCTION:
case ICMPV6_MLD2_REPORT:
break;
default:
err = 0;
goto out;
}
/* Okay, we found MLD message. Check further. */
if (skb2->len > len) {
err = pskb_trim_rcsum(skb2, len);
if (err)
goto out;
err = -EINVAL;
}
ip6h = ipv6_hdr(skb2);
switch (skb2->ip_summed) {
case CHECKSUM_COMPLETE:
if (!csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, skb2->len,
IPPROTO_ICMPV6, skb2->csum))
break;
/*FALLTHROUGH*/
case CHECKSUM_NONE:
skb2->csum = ~csum_unfold(csum_ipv6_magic(&ip6h->saddr,
&ip6h->daddr,
skb2->len,
IPPROTO_ICMPV6, 0));
if (__skb_checksum_complete(skb2))
goto out;
} else if (err < 0) {
return err;
}
err = 0;
BR_INPUT_SKB_CB(skb)->igmp = 1;
mld = (struct mld_msg *)skb_transport_header(skb);
switch (icmp6_type) {
switch (mld->mld_type) {
case ICMPV6_MGM_REPORT:
{
struct mld_msg *mld;
if (!pskb_may_pull(skb2, sizeof(*mld))) {
err = -EINVAL;
goto out;
}
mld = (struct mld_msg *)skb_transport_header(skb2);
BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
err = br_ip6_multicast_add_group(br, port, &mld->mld_mca, vid);
break;
}
case ICMPV6_MLD2_REPORT:
err = br_ip6_multicast_mld2_report(br, port, skb2, vid);
err = br_ip6_multicast_mld2_report(br, port, skb_trimmed, vid);
break;
case ICMPV6_MGM_QUERY:
err = br_ip6_multicast_query(br, port, skb2, vid);
err = br_ip6_multicast_query(br, port, skb_trimmed, vid);
break;
case ICMPV6_MGM_REDUCTION:
{
struct mld_msg *mld;
if (!pskb_may_pull(skb2, sizeof(*mld))) {
err = -EINVAL;
goto out;
}
mld = (struct mld_msg *)skb_transport_header(skb2);
br_ip6_multicast_leave_group(br, port, &mld->mld_mca, vid);
}
break;
}
out:
kfree_skb(skb2);
if (skb_trimmed)
kfree_skb(skb_trimmed);
return err;
}
#endif
......
......@@ -4030,6 +4030,93 @@ int skb_checksum_setup(struct sk_buff *skb, bool recalculate)
}
EXPORT_SYMBOL(skb_checksum_setup);
/**
* skb_checksum_maybe_trim - maybe trims the given skb
* @skb: the skb to check
* @transport_len: the data length beyond the network header
*
* Checks whether the given skb has data beyond the given transport length.
* If so, returns a cloned skb trimmed to this transport length.
* Otherwise returns the provided skb. Returns NULL in error cases
* (e.g. transport_len exceeds skb length or out-of-memory).
*
* Caller needs to set the skb transport header and release the returned skb.
* Provided skb is consumed.
*/
static struct sk_buff *skb_checksum_maybe_trim(struct sk_buff *skb,
unsigned int transport_len)
{
struct sk_buff *skb_chk;
unsigned int len = skb_transport_offset(skb) + transport_len;
int ret;
if (skb->len < len) {
kfree_skb(skb);
return NULL;
} else if (skb->len == len) {
return skb;
}
skb_chk = skb_clone(skb, GFP_ATOMIC);
kfree_skb(skb);
if (!skb_chk)
return NULL;
ret = pskb_trim_rcsum(skb_chk, len);
if (ret) {
kfree_skb(skb_chk);
return NULL;
}
return skb_chk;
}
/**
* skb_checksum_trimmed - validate checksum of an skb
* @skb: the skb to check
* @transport_len: the data length beyond the network header
* @skb_chkf: checksum function to use
*
* Applies the given checksum function skb_chkf to the provided skb.
* Returns a checked and maybe trimmed skb. Returns NULL on error.
*
* If the skb has data beyond the given transport length, then a
* trimmed & cloned skb is checked and returned.
*
* Caller needs to set the skb transport header and release the returned skb.
* Provided skb is consumed.
*/
struct sk_buff *skb_checksum_trimmed(struct sk_buff *skb,
unsigned int transport_len,
__sum16(*skb_chkf)(struct sk_buff *skb))
{
struct sk_buff *skb_chk;
unsigned int offset = skb_transport_offset(skb);
int ret;
skb_chk = skb_checksum_maybe_trim(skb, transport_len);
if (!skb_chk)
return NULL;
if (!pskb_may_pull(skb_chk, offset)) {
kfree_skb(skb_chk);
return NULL;
}
__skb_pull(skb_chk, offset);
ret = skb_chkf(skb_chk);
__skb_push(skb_chk, offset);
if (ret) {
kfree_skb(skb_chk);
return NULL;
}
return skb_chk;
}
EXPORT_SYMBOL(skb_checksum_trimmed);
void __skb_warn_lro_forwarding(const struct sk_buff *skb)
{
net_warn_ratelimited("%s: received packets cannot be forwarded while LRO is enabled\n",
......
......@@ -1339,6 +1339,168 @@ void ip_mc_inc_group(struct in_device *in_dev, __be32 addr)
}
EXPORT_SYMBOL(ip_mc_inc_group);
static int ip_mc_check_iphdr(struct sk_buff *skb)
{
const struct iphdr *iph;
unsigned int len;
unsigned int offset = skb_network_offset(skb) + sizeof(*iph);
if (!pskb_may_pull(skb, offset))
return -EINVAL;
iph = ip_hdr(skb);
if (iph->version != 4 || ip_hdrlen(skb) < sizeof(*iph))
return -EINVAL;
offset += ip_hdrlen(skb) - sizeof(*iph);
if (!pskb_may_pull(skb, offset))
return -EINVAL;
iph = ip_hdr(skb);
if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
return -EINVAL;
len = skb_network_offset(skb) + ntohs(iph->tot_len);
if (skb->len < len || len < offset)
return -EINVAL;
skb_set_transport_header(skb, offset);
return 0;
}
static int ip_mc_check_igmp_reportv3(struct sk_buff *skb)
{
unsigned int len = skb_transport_offset(skb);
len += sizeof(struct igmpv3_report);
return pskb_may_pull(skb, len) ? 0 : -EINVAL;
}
static int ip_mc_check_igmp_query(struct sk_buff *skb)
{
unsigned int len = skb_transport_offset(skb);
len += sizeof(struct igmphdr);
if (skb->len < len)
return -EINVAL;
/* IGMPv{1,2}? */
if (skb->len != len) {
/* or IGMPv3? */
len += sizeof(struct igmpv3_query) - sizeof(struct igmphdr);
if (skb->len < len || !pskb_may_pull(skb, len))
return -EINVAL;
}
/* RFC2236+RFC3376 (IGMPv2+IGMPv3) require the multicast link layer
* all-systems destination addresses (224.0.0.1) for general queries
*/
if (!igmp_hdr(skb)->group &&
ip_hdr(skb)->daddr != htonl(INADDR_ALLHOSTS_GROUP))
return -EINVAL;
return 0;
}
static int ip_mc_check_igmp_msg(struct sk_buff *skb)
{
switch (igmp_hdr(skb)->type) {
case IGMP_HOST_LEAVE_MESSAGE:
case IGMP_HOST_MEMBERSHIP_REPORT:
case IGMPV2_HOST_MEMBERSHIP_REPORT:
/* fall through */
return 0;
case IGMPV3_HOST_MEMBERSHIP_REPORT:
return ip_mc_check_igmp_reportv3(skb);
case IGMP_HOST_MEMBERSHIP_QUERY:
return ip_mc_check_igmp_query(skb);
default:
return -ENOMSG;
}
}
static inline __sum16 ip_mc_validate_checksum(struct sk_buff *skb)
{
return skb_checksum_simple_validate(skb);
}
static int __ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed)
{
struct sk_buff *skb_chk;
unsigned int transport_len;
unsigned int len = skb_transport_offset(skb) + sizeof(struct igmphdr);
int ret;
transport_len = ntohs(ip_hdr(skb)->tot_len) - ip_hdrlen(skb);
skb_get(skb);
skb_chk = skb_checksum_trimmed(skb, transport_len,
ip_mc_validate_checksum);
if (!skb_chk)
return -EINVAL;
if (!pskb_may_pull(skb_chk, len)) {
kfree_skb(skb_chk);
return -EINVAL;
}
ret = ip_mc_check_igmp_msg(skb_chk);
if (ret) {
kfree_skb(skb_chk);
return ret;
}
if (skb_trimmed)
*skb_trimmed = skb_chk;
else
kfree_skb(skb_chk);
return 0;
}
/**
* ip_mc_check_igmp - checks whether this is a sane IGMP packet
* @skb: the skb to validate
* @skb_trimmed: to store an skb pointer trimmed to IPv4 packet tail (optional)
*
* Checks whether an IPv4 packet is a valid IGMP packet. If so sets
* skb network and transport headers accordingly and returns zero.
*
* -EINVAL: A broken packet was detected, i.e. it violates some internet
* standard
* -ENOMSG: IP header validation succeeded but it is not an IGMP packet.
* -ENOMEM: A memory allocation failure happened.
*
* Optionally, an skb pointer might be provided via skb_trimmed (or set it
* to NULL): After parsing an IGMP packet successfully it will point to
* an skb which has its tail aligned to the IP packet end. This might
* either be the originally provided skb or a trimmed, cloned version if
* the skb frame had data beyond the IP packet. A cloned skb allows us
* to leave the original skb and its full frame unchanged (which might be
* desirable for layer 2 frame jugglers).
*
* The caller needs to release a reference count from any returned skb_trimmed.
*/
int ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed)
{
int ret = ip_mc_check_iphdr(skb);
if (ret < 0)
return ret;
if (ip_hdr(skb)->protocol != IPPROTO_IGMP)
return -ENOMSG;
return __ip_mc_check_igmp(skb, skb_trimmed);
}
EXPORT_SYMBOL(ip_mc_check_igmp);
/*
* Resend IGMP JOIN report; used by netdev notifier.
*/
......
......@@ -48,4 +48,5 @@ obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o
ifneq ($(CONFIG_IPV6),)
obj-$(CONFIG_NET_UDP_TUNNEL) += ip6_udp_tunnel.o
obj-y += mcast_snoop.o
endif
/* Copyright (C) 2010: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
* Copyright (C) 2015: Linus Lüssing <linus.luessing@c0d3.blue>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*
*
* Based on the MLD support added to br_multicast.c by YOSHIFUJI Hideaki.
*/
#include <linux/skbuff.h>
#include <net/ipv6.h>
#include <net/mld.h>
#include <net/addrconf.h>
#include <net/ip6_checksum.h>
static int ipv6_mc_check_ip6hdr(struct sk_buff *skb)
{
const struct ipv6hdr *ip6h;
unsigned int len;
unsigned int offset = skb_network_offset(skb) + sizeof(*ip6h);
if (!pskb_may_pull(skb, offset))
return -EINVAL;
ip6h = ipv6_hdr(skb);
if (ip6h->version != 6)
return -EINVAL;
len = offset + ntohs(ip6h->payload_len);
if (skb->len < len || len <= offset)
return -EINVAL;
return 0;
}
static int ipv6_mc_check_exthdrs(struct sk_buff *skb)
{
const struct ipv6hdr *ip6h;
unsigned int offset;
u8 nexthdr;
__be16 frag_off;
ip6h = ipv6_hdr(skb);
if (ip6h->nexthdr != IPPROTO_HOPOPTS)
return -ENOMSG;
nexthdr = ip6h->nexthdr;
offset = skb_network_offset(skb) + sizeof(*ip6h);
offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
if (offset < 0)
return -EINVAL;
if (nexthdr != IPPROTO_ICMPV6)
return -ENOMSG;
skb_set_transport_header(skb, offset);
return 0;
}
static int ipv6_mc_check_mld_reportv2(struct sk_buff *skb)
{
unsigned int len = skb_transport_offset(skb);
len += sizeof(struct mld2_report);
return pskb_may_pull(skb, len) ? 0 : -EINVAL;
}
static int ipv6_mc_check_mld_query(struct sk_buff *skb)
{
struct mld_msg *mld;
unsigned int len = skb_transport_offset(skb);
/* RFC2710+RFC3810 (MLDv1+MLDv2) require link-local source addresses */
if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL))
return -EINVAL;
len += sizeof(struct mld_msg);
if (skb->len < len)
return -EINVAL;
/* MLDv1? */
if (skb->len != len) {
/* or MLDv2? */
len += sizeof(struct mld2_query) - sizeof(struct mld_msg);
if (skb->len < len || !pskb_may_pull(skb, len))
return -EINVAL;
}
mld = (struct mld_msg *)skb_transport_header(skb);
/* RFC2710+RFC3810 (MLDv1+MLDv2) require the multicast link layer
* all-nodes destination address (ff02::1) for general queries
*/
if (ipv6_addr_any(&mld->mld_mca) &&
!ipv6_addr_is_ll_all_nodes(&ipv6_hdr(skb)->daddr))
return -EINVAL;
return 0;
}
static int ipv6_mc_check_mld_msg(struct sk_buff *skb)
{
struct mld_msg *mld = (struct mld_msg *)skb_transport_header(skb);
switch (mld->mld_type) {
case ICMPV6_MGM_REDUCTION:
case ICMPV6_MGM_REPORT:
/* fall through */
return 0;
case ICMPV6_MLD2_REPORT:
return ipv6_mc_check_mld_reportv2(skb);
case ICMPV6_MGM_QUERY:
return ipv6_mc_check_mld_query(skb);
default:
return -ENOMSG;
}
}
static inline __sum16 ipv6_mc_validate_checksum(struct sk_buff *skb)
{
return skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo);
}
static int __ipv6_mc_check_mld(struct sk_buff *skb,
struct sk_buff **skb_trimmed)
{
struct sk_buff *skb_chk = NULL;
unsigned int transport_len;
unsigned int len = skb_transport_offset(skb) + sizeof(struct mld_msg);
int ret;
transport_len = ntohs(ipv6_hdr(skb)->payload_len);
transport_len -= skb_transport_offset(skb) - sizeof(struct ipv6hdr);
skb_get(skb);
skb_chk = skb_checksum_trimmed(skb, transport_len,
ipv6_mc_validate_checksum);
if (!skb_chk)
return -EINVAL;
if (!pskb_may_pull(skb_chk, len)) {
kfree_skb(skb_chk);
return -EINVAL;
}
ret = ipv6_mc_check_mld_msg(skb_chk);
if (ret) {
kfree_skb(skb_chk);
return ret;
}
if (skb_trimmed)
*skb_trimmed = skb_chk;
else
kfree_skb(skb_chk);
return 0;
}
/**
* ipv6_mc_check_mld - checks whether this is a sane MLD packet
* @skb: the skb to validate
* @skb_trimmed: to store an skb pointer trimmed to IPv6 packet tail (optional)
*
* Checks whether an IPv6 packet is a valid MLD packet. If so sets
* skb network and transport headers accordingly and returns zero.
*
* -EINVAL: A broken packet was detected, i.e. it violates some internet
* standard
* -ENOMSG: IP header validation succeeded but it is not an MLD packet.
* -ENOMEM: A memory allocation failure happened.
*
* Optionally, an skb pointer might be provided via skb_trimmed (or set it
* to NULL): After parsing an MLD packet successfully it will point to
* an skb which has its tail aligned to the IP packet end. This might
* either be the originally provided skb or a trimmed, cloned version if
* the skb frame had data beyond the IP packet. A cloned skb allows us
* to leave the original skb and its full frame unchanged (which might be
* desirable for layer 2 frame jugglers).
*
* The caller needs to release a reference count from any returned skb_trimmed.
*/
int ipv6_mc_check_mld(struct sk_buff *skb, struct sk_buff **skb_trimmed)
{
int ret;
ret = ipv6_mc_check_ip6hdr(skb);
if (ret < 0)
return ret;
ret = ipv6_mc_check_exthdrs(skb);
if (ret < 0)
return ret;
return __ipv6_mc_check_mld(skb, skb_trimmed);
}
EXPORT_SYMBOL(ipv6_mc_check_mld);
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