diff options
author | Florian Westphal <fw@strlen.de> | 2015-08-17 18:09:55 +0200 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2015-08-19 08:39:53 +0200 |
commit | 8cfd23e6740158817d2045915f6ea5a2daf11bce (patch) | |
tree | 31e95677b99758f856b9a78f698037ba723e28a3 /net/netfilter/nft_payload.c | |
parent | 5e8018fc61423e677398d4ad4d72df70b9788e77 (diff) | |
download | op-kernel-dev-8cfd23e6740158817d2045915f6ea5a2daf11bce.zip op-kernel-dev-8cfd23e6740158817d2045915f6ea5a2daf11bce.tar.gz |
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>
Diffstat (limited to 'net/netfilter/nft_payload.c')
-rw-r--r-- | net/netfilter/nft_payload.c | 57 |
1 files changed, 56 insertions, 1 deletions
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index 94fb3b2..09b4b07 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -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; |