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netfilter: nft_synproxy: add synproxy stateful object support
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Register a new synproxy stateful object type into the stateful object
infrastructure.

Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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Fernando Fernandez Mancera authored and Pablo Neira Ayuso committed Sep 10, 2019
1 parent 3474a2c commit ee394f9
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Showing 2 changed files with 124 additions and 22 deletions.
3 changes: 2 additions & 1 deletion include/uapi/linux/netfilter/nf_tables.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1481,7 +1481,8 @@ enum nft_ct_expectation_attributes {
#define NFT_OBJECT_CT_TIMEOUT 7
#define NFT_OBJECT_SECMARK 8
#define NFT_OBJECT_CT_EXPECT 9
#define __NFT_OBJECT_MAX 10
#define NFT_OBJECT_SYNPROXY 10
#define __NFT_OBJECT_MAX 11
#define NFT_OBJECT_MAX (__NFT_OBJECT_MAX - 1)

/**
Expand Down
143 changes: 122 additions & 21 deletions net/netfilter/nft_synproxy.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ static void nft_synproxy_tcp_options(struct synproxy_options *opts,
const struct tcphdr *tcp,
struct synproxy_net *snet,
struct nf_synproxy_info *info,
struct nft_synproxy *priv)
const struct nft_synproxy *priv)
{
this_cpu_inc(snet->stats->syn_received);
if (tcp->ece && tcp->cwr)
Expand All @@ -41,14 +41,13 @@ static void nft_synproxy_tcp_options(struct synproxy_options *opts,
NF_SYNPROXY_OPT_ECN);
}

static void nft_synproxy_eval_v4(const struct nft_expr *expr,
static void nft_synproxy_eval_v4(const struct nft_synproxy *priv,
struct nft_regs *regs,
const struct nft_pktinfo *pkt,
const struct tcphdr *tcp,
struct tcphdr *_tcph,
struct synproxy_options *opts)
{
struct nft_synproxy *priv = nft_expr_priv(expr);
struct nf_synproxy_info info = priv->info;
struct net *net = nft_net(pkt);
struct synproxy_net *snet = synproxy_pernet(net);
Expand All @@ -73,14 +72,13 @@ static void nft_synproxy_eval_v4(const struct nft_expr *expr,
}

#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
static void nft_synproxy_eval_v6(const struct nft_expr *expr,
static void nft_synproxy_eval_v6(const struct nft_synproxy *priv,
struct nft_regs *regs,
const struct nft_pktinfo *pkt,
const struct tcphdr *tcp,
struct tcphdr *_tcph,
struct synproxy_options *opts)
{
struct nft_synproxy *priv = nft_expr_priv(expr);
struct nf_synproxy_info info = priv->info;
struct net *net = nft_net(pkt);
struct synproxy_net *snet = synproxy_pernet(net);
Expand All @@ -105,9 +103,9 @@ static void nft_synproxy_eval_v6(const struct nft_expr *expr,
}
#endif /* CONFIG_NF_TABLES_IPV6*/

static void nft_synproxy_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
static void nft_synproxy_do_eval(const struct nft_synproxy *priv,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
struct synproxy_options opts = {};
struct sk_buff *skb = pkt->skb;
Expand Down Expand Up @@ -140,23 +138,22 @@ static void nft_synproxy_eval(const struct nft_expr *expr,

switch (skb->protocol) {
case htons(ETH_P_IP):
nft_synproxy_eval_v4(expr, regs, pkt, tcp, &_tcph, &opts);
nft_synproxy_eval_v4(priv, regs, pkt, tcp, &_tcph, &opts);
return;
#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)
case htons(ETH_P_IPV6):
nft_synproxy_eval_v6(expr, regs, pkt, tcp, &_tcph, &opts);
nft_synproxy_eval_v6(priv, regs, pkt, tcp, &_tcph, &opts);
return;
#endif
}
regs->verdict.code = NFT_BREAK;
}

static int nft_synproxy_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
static int nft_synproxy_do_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[],
struct nft_synproxy *priv)
{
struct synproxy_net *snet = synproxy_pernet(ctx->net);
struct nft_synproxy *priv = nft_expr_priv(expr);
u32 flags;
int err;

Expand Down Expand Up @@ -206,8 +203,7 @@ static int nft_synproxy_init(const struct nft_ctx *ctx,
return err;
}

static void nft_synproxy_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
static void nft_synproxy_do_destroy(const struct nft_ctx *ctx)
{
struct synproxy_net *snet = synproxy_pernet(ctx->net);

Expand All @@ -229,10 +225,8 @@ static void nft_synproxy_destroy(const struct nft_ctx *ctx,
nf_ct_netns_put(ctx->net, ctx->family);
}

static int nft_synproxy_dump(struct sk_buff *skb, const struct nft_expr *expr)
static int nft_synproxy_do_dump(struct sk_buff *skb, struct nft_synproxy *priv)
{
const struct nft_synproxy *priv = nft_expr_priv(expr);

if (nla_put_be16(skb, NFTA_SYNPROXY_MSS, htons(priv->info.mss)) ||
nla_put_u8(skb, NFTA_SYNPROXY_WSCALE, priv->info.wscale) ||
nla_put_be32(skb, NFTA_SYNPROXY_FLAGS, htonl(priv->info.options)))
Expand All @@ -244,6 +238,15 @@ static int nft_synproxy_dump(struct sk_buff *skb, const struct nft_expr *expr)
return -1;
}

static void nft_synproxy_eval(const struct nft_expr *expr,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_synproxy *priv = nft_expr_priv(expr);

nft_synproxy_do_eval(priv, regs, pkt);
}

static int nft_synproxy_validate(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nft_data **data)
Expand All @@ -252,6 +255,28 @@ static int nft_synproxy_validate(const struct nft_ctx *ctx,
(1 << NF_INET_FORWARD));
}

static int nft_synproxy_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
{
struct nft_synproxy *priv = nft_expr_priv(expr);

return nft_synproxy_do_init(ctx, tb, priv);
}

static void nft_synproxy_destroy(const struct nft_ctx *ctx,
const struct nft_expr *expr)
{
nft_synproxy_do_destroy(ctx);
}

static int nft_synproxy_dump(struct sk_buff *skb, const struct nft_expr *expr)
{
struct nft_synproxy *priv = nft_expr_priv(expr);

return nft_synproxy_do_dump(skb, priv);
}

static struct nft_expr_type nft_synproxy_type;
static const struct nft_expr_ops nft_synproxy_ops = {
.eval = nft_synproxy_eval,
Expand All @@ -271,14 +296,89 @@ static struct nft_expr_type nft_synproxy_type __read_mostly = {
.maxattr = NFTA_SYNPROXY_MAX,
};

static int nft_synproxy_obj_init(const struct nft_ctx *ctx,
const struct nlattr * const tb[],
struct nft_object *obj)
{
struct nft_synproxy *priv = nft_obj_data(obj);

return nft_synproxy_do_init(ctx, tb, priv);
}

static void nft_synproxy_obj_destroy(const struct nft_ctx *ctx,
struct nft_object *obj)
{
nft_synproxy_do_destroy(ctx);
}

static int nft_synproxy_obj_dump(struct sk_buff *skb,
struct nft_object *obj, bool reset)
{
struct nft_synproxy *priv = nft_obj_data(obj);

return nft_synproxy_do_dump(skb, priv);
}

static void nft_synproxy_obj_eval(struct nft_object *obj,
struct nft_regs *regs,
const struct nft_pktinfo *pkt)
{
const struct nft_synproxy *priv = nft_obj_data(obj);

nft_synproxy_do_eval(priv, regs, pkt);
}

static void nft_synproxy_obj_update(struct nft_object *obj,
struct nft_object *newobj)
{
struct nft_synproxy *newpriv = nft_obj_data(newobj);
struct nft_synproxy *priv = nft_obj_data(obj);

priv->info = newpriv->info;
}

static struct nft_object_type nft_synproxy_obj_type;
static const struct nft_object_ops nft_synproxy_obj_ops = {
.type = &nft_synproxy_obj_type,
.size = sizeof(struct nft_synproxy),
.init = nft_synproxy_obj_init,
.destroy = nft_synproxy_obj_destroy,
.dump = nft_synproxy_obj_dump,
.eval = nft_synproxy_obj_eval,
.update = nft_synproxy_obj_update,
};

static struct nft_object_type nft_synproxy_obj_type __read_mostly = {
.type = NFT_OBJECT_SYNPROXY,
.ops = &nft_synproxy_obj_ops,
.maxattr = NFTA_SYNPROXY_MAX,
.policy = nft_synproxy_policy,
.owner = THIS_MODULE,
};

static int __init nft_synproxy_module_init(void)
{
return nft_register_expr(&nft_synproxy_type);
int err;

err = nft_register_obj(&nft_synproxy_obj_type);
if (err < 0)
return err;

err = nft_register_expr(&nft_synproxy_type);
if (err < 0)
goto err;

return 0;

err:
nft_unregister_obj(&nft_synproxy_obj_type);
return err;
}

static void __exit nft_synproxy_module_exit(void)
{
return nft_unregister_expr(&nft_synproxy_type);
nft_unregister_expr(&nft_synproxy_type);
nft_unregister_obj(&nft_synproxy_obj_type);
}

module_init(nft_synproxy_module_init);
Expand All @@ -287,3 +387,4 @@ module_exit(nft_synproxy_module_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Fernando Fernandez <ffmancera@riseup.net>");
MODULE_ALIAS_NFT_EXPR("synproxy");
MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_SYNPROXY);

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