diff options
author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-03-25 03:53:42 -0300 |
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committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-03-25 03:53:42 -0300 |
commit | 03dd4cb26d967f9588437b0fc9cc0e8353322bb7 (patch) | |
tree | fa581f6dc1c0596391690d1f67eceef3af8246dc /net/netfilter/nf_tables_trace.c | |
parent | d4e493caf788ef44982e131ff9c786546904d934 (diff) |
Linux-libre 4.5-gnu
Diffstat (limited to 'net/netfilter/nf_tables_trace.c')
-rw-r--r-- | net/netfilter/nf_tables_trace.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/net/netfilter/nf_tables_trace.c b/net/netfilter/nf_tables_trace.c new file mode 100644 index 000000000..e9e959f65 --- /dev/null +++ b/net/netfilter/nf_tables_trace.c @@ -0,0 +1,275 @@ +/* + * (C) 2015 Red Hat GmbH + * Author: Florian Westphal <fw@strlen.de> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/static_key.h> +#include <linux/hash.h> +#include <linux/jhash.h> +#include <linux/if_vlan.h> +#include <linux/init.h> +#include <linux/skbuff.h> +#include <linux/netlink.h> +#include <linux/netfilter.h> +#include <linux/netfilter/nfnetlink.h> +#include <linux/netfilter/nf_tables.h> +#include <net/netfilter/nf_tables_core.h> +#include <net/netfilter/nf_tables.h> + +#define NFT_TRACETYPE_LL_HSIZE 20 +#define NFT_TRACETYPE_NETWORK_HSIZE 40 +#define NFT_TRACETYPE_TRANSPORT_HSIZE 20 + +DEFINE_STATIC_KEY_FALSE(nft_trace_enabled); +EXPORT_SYMBOL_GPL(nft_trace_enabled); + +static int trace_fill_id(struct sk_buff *nlskb, struct sk_buff *skb) +{ + __be32 id; + + /* using skb address as ID results in a limited number of + * values (and quick reuse). + * + * So we attempt to use as many skb members that will not + * change while skb is with netfilter. + */ + id = (__be32)jhash_2words(hash32_ptr(skb), skb_get_hash(skb), + skb->skb_iif); + + return nla_put_be32(nlskb, NFTA_TRACE_ID, id); +} + +static int trace_fill_header(struct sk_buff *nlskb, u16 type, + const struct sk_buff *skb, + int off, unsigned int len) +{ + struct nlattr *nla; + + if (len == 0) + return 0; + + nla = nla_reserve(nlskb, type, len); + if (!nla || skb_copy_bits(skb, off, nla_data(nla), len)) + return -1; + + return 0; +} + +static int nf_trace_fill_ll_header(struct sk_buff *nlskb, + const struct sk_buff *skb) +{ + struct vlan_ethhdr veth; + int off; + + BUILD_BUG_ON(sizeof(veth) > NFT_TRACETYPE_LL_HSIZE); + + off = skb_mac_header(skb) - skb->data; + if (off != -ETH_HLEN) + return -1; + + if (skb_copy_bits(skb, off, &veth, ETH_HLEN)) + return -1; + + veth.h_vlan_proto = skb->vlan_proto; + veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); + veth.h_vlan_encapsulated_proto = skb->protocol; + + return nla_put(nlskb, NFTA_TRACE_LL_HEADER, sizeof(veth), &veth); +} + +static int nf_trace_fill_dev_info(struct sk_buff *nlskb, + const struct net_device *indev, + const struct net_device *outdev) +{ + if (indev) { + if (nla_put_be32(nlskb, NFTA_TRACE_IIF, + htonl(indev->ifindex))) + return -1; + + if (nla_put_be16(nlskb, NFTA_TRACE_IIFTYPE, + htons(indev->type))) + return -1; + } + + if (outdev) { + if (nla_put_be32(nlskb, NFTA_TRACE_OIF, + htonl(outdev->ifindex))) + return -1; + + if (nla_put_be16(nlskb, NFTA_TRACE_OIFTYPE, + htons(outdev->type))) + return -1; + } + + return 0; +} + +static int nf_trace_fill_pkt_info(struct sk_buff *nlskb, + const struct nft_pktinfo *pkt) +{ + const struct sk_buff *skb = pkt->skb; + unsigned int len = min_t(unsigned int, + pkt->xt.thoff - skb_network_offset(skb), + NFT_TRACETYPE_NETWORK_HSIZE); + int off = skb_network_offset(skb); + + if (trace_fill_header(nlskb, NFTA_TRACE_NETWORK_HEADER, skb, off, len)) + return -1; + + len = min_t(unsigned int, skb->len - pkt->xt.thoff, + NFT_TRACETYPE_TRANSPORT_HSIZE); + + if (trace_fill_header(nlskb, NFTA_TRACE_TRANSPORT_HEADER, skb, + pkt->xt.thoff, len)) + return -1; + + if (!skb_mac_header_was_set(skb)) + return 0; + + if (skb_vlan_tag_get(skb)) + return nf_trace_fill_ll_header(nlskb, skb); + + off = skb_mac_header(skb) - skb->data; + len = min_t(unsigned int, -off, NFT_TRACETYPE_LL_HSIZE); + return trace_fill_header(nlskb, NFTA_TRACE_LL_HEADER, + skb, off, len); +} + +static int nf_trace_fill_rule_info(struct sk_buff *nlskb, + const struct nft_traceinfo *info) +{ + if (!info->rule) + return 0; + + /* a continue verdict with ->type == RETURN means that this is + * an implicit return (end of chain reached). + * + * Since no rule matched, the ->rule pointer is invalid. + */ + if (info->type == NFT_TRACETYPE_RETURN && + info->verdict->code == NFT_CONTINUE) + return 0; + + return nla_put_be64(nlskb, NFTA_TRACE_RULE_HANDLE, + cpu_to_be64(info->rule->handle)); +} + +void nft_trace_notify(struct nft_traceinfo *info) +{ + const struct nft_pktinfo *pkt = info->pkt; + struct nfgenmsg *nfmsg; + struct nlmsghdr *nlh; + struct sk_buff *skb; + unsigned int size; + int event = (NFNL_SUBSYS_NFTABLES << 8) | NFT_MSG_TRACE; + + if (!nfnetlink_has_listeners(pkt->net, NFNLGRP_NFTRACE)) + return; + + size = nlmsg_total_size(sizeof(struct nfgenmsg)) + + nla_total_size(NFT_TABLE_MAXNAMELEN) + + nla_total_size(NFT_CHAIN_MAXNAMELEN) + + nla_total_size(sizeof(__be64)) + /* rule handle */ + nla_total_size(sizeof(__be32)) + /* trace type */ + nla_total_size(0) + /* VERDICT, nested */ + nla_total_size(sizeof(u32)) + /* verdict code */ + nla_total_size(NFT_CHAIN_MAXNAMELEN) + /* jump target */ + nla_total_size(sizeof(u32)) + /* id */ + nla_total_size(NFT_TRACETYPE_LL_HSIZE) + + nla_total_size(NFT_TRACETYPE_NETWORK_HSIZE) + + nla_total_size(NFT_TRACETYPE_TRANSPORT_HSIZE) + + nla_total_size(sizeof(u32)) + /* iif */ + nla_total_size(sizeof(__be16)) + /* iiftype */ + nla_total_size(sizeof(u32)) + /* oif */ + nla_total_size(sizeof(__be16)) + /* oiftype */ + nla_total_size(sizeof(u32)) + /* mark */ + nla_total_size(sizeof(u32)) + /* nfproto */ + nla_total_size(sizeof(u32)); /* policy */ + + skb = nlmsg_new(size, GFP_ATOMIC); + if (!skb) + return; + + nlh = nlmsg_put(skb, 0, 0, event, sizeof(struct nfgenmsg), 0); + if (!nlh) + goto nla_put_failure; + + nfmsg = nlmsg_data(nlh); + nfmsg->nfgen_family = info->basechain->type->family; + nfmsg->version = NFNETLINK_V0; + nfmsg->res_id = 0; + + if (nla_put_be32(skb, NFTA_TRACE_NFPROTO, htonl(pkt->pf))) + goto nla_put_failure; + + if (nla_put_be32(skb, NFTA_TRACE_TYPE, htonl(info->type))) + goto nla_put_failure; + + if (trace_fill_id(skb, pkt->skb)) + goto nla_put_failure; + + if (info->chain) { + if (nla_put_string(skb, NFTA_TRACE_CHAIN, + info->chain->name)) + goto nla_put_failure; + if (nla_put_string(skb, NFTA_TRACE_TABLE, + info->chain->table->name)) + goto nla_put_failure; + } + + if (nf_trace_fill_rule_info(skb, info)) + goto nla_put_failure; + + switch (info->type) { + case NFT_TRACETYPE_UNSPEC: + case __NFT_TRACETYPE_MAX: + break; + case NFT_TRACETYPE_RETURN: + case NFT_TRACETYPE_RULE: + if (nft_verdict_dump(skb, NFTA_TRACE_VERDICT, info->verdict)) + goto nla_put_failure; + break; + case NFT_TRACETYPE_POLICY: + if (nla_put_be32(skb, NFTA_TRACE_POLICY, + info->basechain->policy)) + goto nla_put_failure; + break; + } + + if (pkt->skb->mark && + nla_put_be32(skb, NFTA_TRACE_MARK, htonl(pkt->skb->mark))) + goto nla_put_failure; + + if (!info->packet_dumped) { + if (nf_trace_fill_dev_info(skb, pkt->in, pkt->out)) + goto nla_put_failure; + + if (nf_trace_fill_pkt_info(skb, pkt)) + goto nla_put_failure; + info->packet_dumped = true; + } + + nlmsg_end(skb, nlh); + nfnetlink_send(skb, pkt->net, 0, NFNLGRP_NFTRACE, 0, GFP_ATOMIC); + return; + + nla_put_failure: + WARN_ON_ONCE(1); + kfree_skb(skb); +} + +void nft_trace_init(struct nft_traceinfo *info, const struct nft_pktinfo *pkt, + const struct nft_verdict *verdict, + const struct nft_chain *chain) +{ + info->basechain = nft_base_chain(chain); + info->trace = true; + info->packet_dumped = false; + info->pkt = pkt; + info->verdict = verdict; +} |