From 51b0a5d8c21a91801bbef9bcc8639dc0b206c6cd Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 26 Sep 2014 14:35:14 +0200 Subject: netfilter: nft_reject: introduce icmp code abstraction for inet and bridge This patch introduces the NFT_REJECT_ICMPX_UNREACH type which provides an abstraction to the ICMP and ICMPv6 codes that you can use from the inet and bridge tables, they are: * NFT_REJECT_ICMPX_NO_ROUTE: no route to host - network unreachable * NFT_REJECT_ICMPX_PORT_UNREACH: port unreachable * NFT_REJECT_ICMPX_HOST_UNREACH: host unreachable * NFT_REJECT_ICMPX_ADMIN_PROHIBITED: administratevely prohibited You can still use the specific codes when restricting the rule to match the corresponding layer 3 protocol. I decided to not overload the existing NFT_REJECT_ICMP_UNREACH to have different semantics depending on the table family and to allow the user to specify ICMP family specific codes if they restrict it to the corresponding family. Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/nft_reject_bridge.c | 95 ++++++++++++++++++++++++++++++-- 1 file changed, 90 insertions(+), 5 deletions(-) (limited to 'net/bridge') diff --git a/net/bridge/netfilter/nft_reject_bridge.c b/net/bridge/netfilter/nft_reject_bridge.c index ee3ffe93e14e..a76479535df2 100644 --- a/net/bridge/netfilter/nft_reject_bridge.c +++ b/net/bridge/netfilter/nft_reject_bridge.c @@ -14,21 +14,106 @@ #include #include #include +#include +#include static void nft_reject_bridge_eval(const struct nft_expr *expr, struct nft_data data[NFT_REG_MAX + 1], const struct nft_pktinfo *pkt) { + struct nft_reject *priv = nft_expr_priv(expr); + struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out); + switch (eth_hdr(pkt->skb)->h_proto) { case htons(ETH_P_IP): - return nft_reject_ipv4_eval(expr, data, pkt); + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + nf_send_unreach(pkt->skb, priv->icmp_code); + break; + case NFT_REJECT_TCP_RST: + nf_send_reset(pkt->skb, pkt->ops->hooknum); + break; + case NFT_REJECT_ICMPX_UNREACH: + nf_send_unreach(pkt->skb, + nft_reject_icmp_code(priv->icmp_code)); + break; + } + break; case htons(ETH_P_IPV6): - return nft_reject_ipv6_eval(expr, data, pkt); + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + nf_send_unreach6(net, pkt->skb, priv->icmp_code, + pkt->ops->hooknum); + break; + case NFT_REJECT_TCP_RST: + nf_send_reset6(net, pkt->skb, pkt->ops->hooknum); + break; + case NFT_REJECT_ICMPX_UNREACH: + nf_send_unreach6(net, pkt->skb, + nft_reject_icmpv6_code(priv->icmp_code), + pkt->ops->hooknum); + break; + } + break; default: /* No explicit way to reject this protocol, drop it. */ - data[NFT_REG_VERDICT].verdict = NF_DROP; break; } + data[NFT_REG_VERDICT].verdict = NF_DROP; +} + +static int nft_reject_bridge_init(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nlattr * const tb[]) +{ + struct nft_reject *priv = nft_expr_priv(expr); + int icmp_code; + + if (tb[NFTA_REJECT_TYPE] == NULL) + return -EINVAL; + + priv->type = ntohl(nla_get_be32(tb[NFTA_REJECT_TYPE])); + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + case NFT_REJECT_ICMPX_UNREACH: + if (tb[NFTA_REJECT_ICMP_CODE] == NULL) + return -EINVAL; + + icmp_code = nla_get_u8(tb[NFTA_REJECT_ICMP_CODE]); + if (priv->type == NFT_REJECT_ICMPX_UNREACH && + icmp_code > NFT_REJECT_ICMPX_MAX) + return -EINVAL; + + priv->icmp_code = icmp_code; + break; + case NFT_REJECT_TCP_RST: + break; + default: + return -EINVAL; + } + return 0; +} + +static int nft_reject_bridge_dump(struct sk_buff *skb, + const struct nft_expr *expr) +{ + const struct nft_reject *priv = nft_expr_priv(expr); + + if (nla_put_be32(skb, NFTA_REJECT_TYPE, htonl(priv->type))) + goto nla_put_failure; + + switch (priv->type) { + case NFT_REJECT_ICMP_UNREACH: + case NFT_REJECT_ICMPX_UNREACH: + if (nla_put_u8(skb, NFTA_REJECT_ICMP_CODE, priv->icmp_code)) + goto nla_put_failure; + break; + } + + return 0; + +nla_put_failure: + return -1; } static struct nft_expr_type nft_reject_bridge_type; @@ -36,8 +121,8 @@ static const struct nft_expr_ops nft_reject_bridge_ops = { .type = &nft_reject_bridge_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_reject)), .eval = nft_reject_bridge_eval, - .init = nft_reject_init, - .dump = nft_reject_dump, + .init = nft_reject_bridge_init, + .dump = nft_reject_bridge_dump, }; static struct nft_expr_type nft_reject_bridge_type __read_mostly = { -- cgit v1.2.3