mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-12 05:24:12 +08:00
netfilter: nft_payload: work around vlan header stripping
make payload expression aware of the fact that VLAN offload may have removed a vlan header. When we encounter tagged skb, transparently insert the tag into the register so that vlan header matching can work without userspace being aware of offload features. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
parent
5e8018fc61
commit
8cfd23e674
@ -9,6 +9,7 @@
|
||||
*/
|
||||
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/if_vlan.h>
|
||||
#include <linux/init.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/netlink.h>
|
||||
@ -17,6 +18,53 @@
|
||||
#include <net/netfilter/nf_tables_core.h>
|
||||
#include <net/netfilter/nf_tables.h>
|
||||
|
||||
/* add vlan header into the user buffer for if tag was removed by offloads */
|
||||
static bool
|
||||
nft_payload_copy_vlan(u32 *d, const struct sk_buff *skb, u8 offset, u8 len)
|
||||
{
|
||||
int mac_off = skb_mac_header(skb) - skb->data;
|
||||
u8 vlan_len, *vlanh, *dst_u8 = (u8 *) d;
|
||||
struct vlan_ethhdr veth;
|
||||
|
||||
vlanh = (u8 *) &veth;
|
||||
if (offset < ETH_HLEN) {
|
||||
u8 ethlen = min_t(u8, len, ETH_HLEN - offset);
|
||||
|
||||
if (skb_copy_bits(skb, mac_off, &veth, ETH_HLEN))
|
||||
return false;
|
||||
|
||||
veth.h_vlan_proto = skb->vlan_proto;
|
||||
|
||||
memcpy(dst_u8, vlanh + offset, ethlen);
|
||||
|
||||
len -= ethlen;
|
||||
if (len == 0)
|
||||
return true;
|
||||
|
||||
dst_u8 += ethlen;
|
||||
offset = ETH_HLEN;
|
||||
} else if (offset >= VLAN_ETH_HLEN) {
|
||||
offset -= VLAN_HLEN;
|
||||
goto skip;
|
||||
}
|
||||
|
||||
veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
|
||||
veth.h_vlan_encapsulated_proto = skb->protocol;
|
||||
|
||||
vlanh += offset;
|
||||
|
||||
vlan_len = min_t(u8, len, VLAN_ETH_HLEN - offset);
|
||||
memcpy(dst_u8, vlanh, vlan_len);
|
||||
|
||||
len -= vlan_len;
|
||||
if (!len)
|
||||
return true;
|
||||
|
||||
dst_u8 += vlan_len;
|
||||
skip:
|
||||
return skb_copy_bits(skb, offset + mac_off, dst_u8, len) == 0;
|
||||
}
|
||||
|
||||
static void nft_payload_eval(const struct nft_expr *expr,
|
||||
struct nft_regs *regs,
|
||||
const struct nft_pktinfo *pkt)
|
||||
@ -26,10 +74,18 @@ static void nft_payload_eval(const struct nft_expr *expr,
|
||||
u32 *dest = ®s->data[priv->dreg];
|
||||
int offset;
|
||||
|
||||
dest[priv->len / NFT_REG32_SIZE] = 0;
|
||||
switch (priv->base) {
|
||||
case NFT_PAYLOAD_LL_HEADER:
|
||||
if (!skb_mac_header_was_set(skb))
|
||||
goto err;
|
||||
|
||||
if (skb_vlan_tag_present(skb)) {
|
||||
if (!nft_payload_copy_vlan(dest, skb,
|
||||
priv->offset, priv->len))
|
||||
goto err;
|
||||
return;
|
||||
}
|
||||
offset = skb_mac_header(skb) - skb->data;
|
||||
break;
|
||||
case NFT_PAYLOAD_NETWORK_HEADER:
|
||||
@ -43,7 +99,6 @@ static void nft_payload_eval(const struct nft_expr *expr,
|
||||
}
|
||||
offset += priv->offset;
|
||||
|
||||
dest[priv->len / NFT_REG32_SIZE] = 0;
|
||||
if (skb_copy_bits(skb, offset, dest, priv->len) < 0)
|
||||
goto err;
|
||||
return;
|
||||
|
Loading…
Reference in New Issue
Block a user