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netfilter: flowtable: split IPv4 datapath in helper functions

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Add context structure and helper functions to look up for a matching
IPv4 entry in the flowtable and to forward packets.

No functional changes are intended.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
This commit is contained in:
Pablo Neira Ayuso 2023-05-11 07:35:34 +02:00 committed by Florian Westphal
parent fa502c8656
commit a10fa0b489
1 changed files with 77 additions and 42 deletions
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119
net/netfilter/nf_flow_table_ip.c
View File

@ -163,38 +163,43 @@ static void nf_flow_tuple_encap(struct sk_buff *skb,
}
}
static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
struct flow_offload_tuple *tuple, u32 *hdrsize,
u32 offset)
struct nf_flowtable_ctx {
const struct net_device *in;
u32 offset;
u32 hdrsize;
};
static int nf_flow_tuple_ip(struct nf_flowtable_ctx *ctx, struct sk_buff *skb,
struct flow_offload_tuple *tuple)
{
struct flow_ports *ports;
unsigned int thoff;
struct iphdr *iph;
u8 ipproto;
if (!pskb_may_pull(skb, sizeof(*iph) + offset))
if (!pskb_may_pull(skb, sizeof(*iph) + ctx->offset))
return -1;
iph = (struct iphdr *)(skb_network_header(skb) + offset);
iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset);
thoff = (iph->ihl * 4);
if (ip_is_fragment(iph) ||
unlikely(ip_has_options(thoff)))
return -1;
thoff += offset;
thoff += ctx->offset;
ipproto = iph->protocol;
switch (ipproto) {
case IPPROTO_TCP:
*hdrsize = sizeof(struct tcphdr);
ctx->hdrsize = sizeof(struct tcphdr);
break;
case IPPROTO_UDP:
*hdrsize = sizeof(struct udphdr);
ctx->hdrsize = sizeof(struct udphdr);
break;
#ifdef CONFIG_NF_CT_PROTO_GRE
case IPPROTO_GRE:
*hdrsize = sizeof(struct gre_base_hdr);
ctx->hdrsize = sizeof(struct gre_base_hdr);
break;
#endif
default:
@ -204,7 +209,7 @@ static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
if (iph->ttl <= 1)
return -1;
if (!pskb_may_pull(skb, thoff + *hdrsize))
if (!pskb_may_pull(skb, thoff + ctx->hdrsize))
return -1;
switch (ipproto) {
@ -224,13 +229,13 @@ static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
}
}
iph = (struct iphdr *)(skb_network_header(skb) + offset);
iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset);
tuple->src_v4.s_addr = iph->saddr;
tuple->dst_v4.s_addr = iph->daddr;
tuple->l3proto = AF_INET;
tuple->l4proto = ipproto;
tuple->iifidx = dev->ifindex;
tuple->iifidx = ctx->in->ifindex;
nf_flow_tuple_encap(skb, tuple);
return 0;
@ -336,58 +341,56 @@ static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb,
return NF_STOLEN;
}
unsigned int
nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
static struct flow_offload_tuple_rhash *
nf_flow_offload_lookup(struct nf_flowtable_ctx *ctx,
struct nf_flowtable *flow_table, struct sk_buff *skb)
{
struct flow_offload_tuple_rhash *tuplehash;
struct nf_flowtable *flow_table = priv;
struct flow_offload_tuple tuple = {};
enum flow_offload_tuple_dir dir;
struct flow_offload *flow;
struct net_device *outdev;
u32 hdrsize, offset = 0;
unsigned int thoff, mtu;
struct rtable *rt;
struct iphdr *iph;
__be32 nexthop;
int ret;
if (skb->protocol != htons(ETH_P_IP) &&
!nf_flow_skb_encap_protocol(skb, htons(ETH_P_IP), &offset))
return NF_ACCEPT;
!nf_flow_skb_encap_protocol(skb, htons(ETH_P_IP), &ctx->offset))
return NULL;
if (nf_flow_tuple_ip(skb, state->in, &tuple, &hdrsize, offset) < 0)
return NF_ACCEPT;
if (nf_flow_tuple_ip(ctx, skb, &tuple) < 0)
return NULL;
tuplehash = flow_offload_lookup(flow_table, &tuple);
if (tuplehash == NULL)
return NF_ACCEPT;
return flow_offload_lookup(flow_table, &tuple);
}
static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx,
struct nf_flowtable *flow_table,
struct flow_offload_tuple_rhash *tuplehash,
struct sk_buff *skb)
{
enum flow_offload_tuple_dir dir;
struct flow_offload *flow;
unsigned int thoff, mtu;
struct iphdr *iph;
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
mtu = flow->tuplehash[dir].tuple.mtu + offset;
mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset;
if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
return NF_ACCEPT;
return 0;
iph = (struct iphdr *)(skb_network_header(skb) + offset);
thoff = (iph->ihl * 4) + offset;
iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset);
thoff = (iph->ihl * 4) + ctx->offset;
if (nf_flow_state_check(flow, iph->protocol, skb, thoff))
return NF_ACCEPT;
return 0;
if (!nf_flow_dst_check(&tuplehash->tuple)) {
flow_offload_teardown(flow);
return NF_ACCEPT;
return 0;
}
if (skb_try_make_writable(skb, thoff + hdrsize))
return NF_DROP;
if (skb_try_make_writable(skb, thoff + ctx->hdrsize))
return -1;
flow_offload_refresh(flow_table, flow);
nf_flow_encap_pop(skb, tuplehash);
thoff -= offset;
thoff -= ctx->offset;
iph = ip_hdr(skb);
nf_flow_nat_ip(flow, skb, thoff, dir, iph);
@ -398,6 +401,35 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
if (flow_table->flags & NF_FLOWTABLE_COUNTER)
nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len);
return 1;
}
unsigned int
nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
{
struct flow_offload_tuple_rhash *tuplehash;
struct nf_flowtable *flow_table = priv;
enum flow_offload_tuple_dir dir;
struct nf_flowtable_ctx ctx = {
.in = state->in,
};
struct flow_offload *flow;
struct net_device *outdev;
struct rtable *rt;
__be32 nexthop;
int ret;
tuplehash = nf_flow_offload_lookup(&ctx, flow_table, skb);
if (!tuplehash)
return NF_ACCEPT;
ret = nf_flow_offload_forward(&ctx, flow_table, tuplehash, skb);
if (ret < 0)
return NF_DROP;
else if (ret == 0)
return NF_ACCEPT;
if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) {
rt = (struct rtable *)tuplehash->tuple.dst_cache;
memset(skb->cb, 0, sizeof(struct inet_skb_parm));
@ -406,6 +438,9 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
return nf_flow_xmit_xfrm(skb, state, &rt->dst);
}
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
switch (tuplehash->tuple.xmit_type) {
case FLOW_OFFLOAD_XMIT_NEIGH:
rt = (struct rtable *)tuplehash->tuple.dst_cache;