| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * (C) 2015 Red Hat GmbH |
| * Author: Florian Westphal <fw@strlen.de> |
| */ |
| |
| #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; |
| int off = skb_network_offset(skb); |
| unsigned int len, nh_end; |
| |
| nh_end = pkt->tprot_set ? pkt->xt.thoff : skb->len; |
| len = min_t(unsigned int, nh_end - skb_network_offset(skb), |
| NFT_TRACETYPE_NETWORK_HSIZE); |
| if (trace_fill_header(nlskb, NFTA_TRACE_NETWORK_HEADER, skb, off, len)) |
| return -1; |
| |
| if (pkt->tprot_set) { |
| 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), |
| NFTA_TRACE_PAD); |
| } |
| |
| static bool nft_trace_have_verdict_chain(struct nft_traceinfo *info) |
| { |
| switch (info->type) { |
| case NFT_TRACETYPE_RETURN: |
| case NFT_TRACETYPE_RULE: |
| break; |
| default: |
| return false; |
| } |
| |
| switch (info->verdict->code) { |
| case NFT_JUMP: |
| case NFT_GOTO: |
| break; |
| default: |
| return false; |
| } |
| |
| return true; |
| } |
| |
| 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; |
| u16 event; |
| |
| if (!nfnetlink_has_listeners(nft_net(pkt), NFNLGRP_NFTRACE)) |
| return; |
| |
| size = nlmsg_total_size(sizeof(struct nfgenmsg)) + |
| nla_total_size(strlen(info->chain->table->name)) + |
| nla_total_size(strlen(info->chain->name)) + |
| nla_total_size_64bit(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(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 */ |
| |
| if (nft_trace_have_verdict_chain(info)) |
| size += nla_total_size(strlen(info->verdict->chain->name)); /* jump target */ |
| |
| skb = nlmsg_new(size, GFP_ATOMIC); |
| if (!skb) |
| return; |
| |
| event = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, NFT_MSG_TRACE); |
| 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(nft_pf(pkt)))) |
| 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 (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, |
| htonl(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, nft_in(pkt), nft_out(pkt))) |
| 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, nft_net(pkt), 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; |
| } |