From 3f3909afd76d2b4d1af0f133c7fe5dc258fcb694 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 2 Jan 2023 15:15:48 +0100 Subject: expr: add inner support This patch adds support for the inner expression which allows you to match on the inner tunnel headers, eg. VxLAN. Signed-off-by: Pablo Neira Ayuso --- include/libnftnl/expr.h | 7 ++ include/linux/netfilter/nf_tables.h | 32 +++++- src/Makefile.am | 1 + src/expr/inner.c | 214 ++++++++++++++++++++++++++++++++++++ src/expr/payload.c | 3 +- src/expr_ops.c | 2 + 6 files changed, 256 insertions(+), 3 deletions(-) create mode 100644 src/expr/inner.c diff --git a/include/libnftnl/expr.h b/include/libnftnl/expr.h index 00c63ab..9873228 100644 --- a/include/libnftnl/expr.h +++ b/include/libnftnl/expr.h @@ -316,6 +316,13 @@ enum { NFTNL_EXPR_LAST_SET, }; +enum { + NFTNL_EXPR_INNER_TYPE = NFTNL_EXPR_BASE, + NFTNL_EXPR_INNER_FLAGS, + NFTNL_EXPR_INNER_HDRSIZE, + NFTNL_EXPR_INNER_EXPR, +}; + #ifdef __cplusplus } /* extern "C" */ #endif diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h index 0ae9120..4608646 100644 --- a/include/linux/netfilter/nf_tables.h +++ b/include/linux/netfilter/nf_tables.h @@ -753,13 +753,14 @@ enum nft_dynset_attributes { * @NFT_PAYLOAD_LL_HEADER: link layer header * @NFT_PAYLOAD_NETWORK_HEADER: network header * @NFT_PAYLOAD_TRANSPORT_HEADER: transport header - * @NFT_PAYLOAD_INNER_HEADER: inner header + * @NFT_PAYLOAD_INNER_HEADER: inner header / payload */ enum nft_payload_bases { NFT_PAYLOAD_LL_HEADER, NFT_PAYLOAD_NETWORK_HEADER, NFT_PAYLOAD_TRANSPORT_HEADER, NFT_PAYLOAD_INNER_HEADER, + NFT_PAYLOAD_TUN_HEADER, }; /** @@ -779,6 +780,31 @@ enum nft_payload_csum_flags { NFT_PAYLOAD_L4CSUM_PSEUDOHDR = (1 << 0), }; +enum nft_inner_type { + NFT_INNER_UNSPEC = 0, + NFT_INNER_VXLAN, +}; + +enum nft_inner_flags { + NFT_INNER_HDRSIZE = (1 << 0), + NFT_INNER_LL = (1 << 1), + NFT_INNER_NH = (1 << 2), + NFT_INNER_TH = (1 << 3), +}; +#define NFT_INNER_MASK (NFT_INNER_HDRSIZE | NFT_INNER_LL | \ + NFT_INNER_NH | NFT_INNER_TH) + +enum nft_inner_attributes { + NFTA_INNER_UNSPEC, + NFTA_INNER_NUM, + NFTA_INNER_TYPE, + NFTA_INNER_FLAGS, + NFTA_INNER_HDRSIZE, + NFTA_INNER_EXPR, + __NFTA_INNER_MAX +}; +#define NFTA_INNER_MAX (__NFTA_INNER_MAX - 1) + /** * enum nft_payload_attributes - nf_tables payload expression netlink attributes * @@ -898,7 +924,8 @@ enum nft_meta_keys { NFT_META_OIF, NFT_META_IIFNAME, NFT_META_OIFNAME, - NFT_META_IIFTYPE, + NFT_META_IFTYPE, +#define NFT_META_IIFTYPE NFT_META_IFTYPE NFT_META_OIFTYPE, NFT_META_SKUID, NFT_META_SKGID, @@ -925,6 +952,7 @@ enum nft_meta_keys { NFT_META_TIME_HOUR, NFT_META_SDIF, NFT_META_SDIFNAME, + __NFT_META_IIFTYPE, }; /** diff --git a/src/Makefile.am b/src/Makefile.am index c3b0ab9..3cd259c 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -40,6 +40,7 @@ libnftnl_la_SOURCES = utils.c \ expr/lookup.c \ expr/dynset.c \ expr/immediate.c \ + expr/inner.c \ expr/match.c \ expr/meta.c \ expr/numgen.c \ diff --git a/src/expr/inner.c b/src/expr/inner.c new file mode 100644 index 0000000..7daae4f --- /dev/null +++ b/src/expr/inner.c @@ -0,0 +1,214 @@ +/* + * (C) 2012-2022 by Pablo Neira Ayuso + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include "internal.h" + +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include + +struct nftnl_expr_inner { + uint32_t type; + uint32_t flags; + uint32_t hdrsize; + struct nftnl_expr *expr; +}; + +static void nftnl_expr_inner_free(const struct nftnl_expr *e) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + + if (inner->expr) + nftnl_expr_free(inner->expr); +} + +static int +nftnl_expr_inner_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_INNER_TYPE: + memcpy(&inner->type, data, sizeof(inner->type)); + break; + case NFTNL_EXPR_INNER_FLAGS: + memcpy(&inner->flags, data, sizeof(inner->flags)); + break; + case NFTNL_EXPR_INNER_HDRSIZE: + memcpy(&inner->hdrsize, data, sizeof(inner->hdrsize)); + break; + case NFTNL_EXPR_INNER_EXPR: + if (inner->expr) + nftnl_expr_free(inner->expr); + + inner->expr = (void *)data; + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_inner_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_INNER_FLAGS: + *data_len = sizeof(inner->flags); + return &inner->flags; + case NFTNL_EXPR_INNER_TYPE: + *data_len = sizeof(inner->type); + return &inner->type; + case NFTNL_EXPR_INNER_HDRSIZE: + *data_len = sizeof(inner->hdrsize); + return &inner->hdrsize; + case NFTNL_EXPR_INNER_EXPR: + return inner->expr; + } + return NULL; +} + +static void +nftnl_expr_inner_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + struct nlattr *nest; + + mnl_attr_put_u32(nlh, NFTA_INNER_NUM, htonl(0)); + if (e->flags & (1 << NFTNL_EXPR_INNER_TYPE)) + mnl_attr_put_u32(nlh, NFTA_INNER_TYPE, htonl(inner->type)); + if (e->flags & (1 << NFTNL_EXPR_INNER_FLAGS)) + mnl_attr_put_u32(nlh, NFTA_INNER_FLAGS, htonl(inner->flags)); + if (e->flags & (1 << NFTNL_EXPR_INNER_HDRSIZE)) + mnl_attr_put_u32(nlh, NFTA_INNER_HDRSIZE, htonl(inner->hdrsize)); + if (e->flags & (1 << NFTNL_EXPR_INNER_EXPR)) { + nest = mnl_attr_nest_start(nlh, NFTA_INNER_EXPR); + nftnl_expr_build_payload(nlh, inner->expr); + mnl_attr_nest_end(nlh, nest); + } +} + +static int nftnl_inner_parse_cb(const struct nlattr *attr, void *data) +{ + const struct nlattr **tb = data; + int type = mnl_attr_get_type(attr); + + if (mnl_attr_type_valid(attr, NFTA_INNER_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_INNER_NUM: + case NFTA_INNER_TYPE: + case NFTA_INNER_HDRSIZE: + case NFTA_INNER_FLAGS: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + case NFTA_INNER_EXPR: + if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + + return MNL_CB_OK; +} + +static int +nftnl_expr_inner_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + struct nlattr *tb[NFTA_INNER_MAX + 1] = {}; + struct nftnl_expr *expr; + int err; + + err = mnl_attr_parse_nested(attr, nftnl_inner_parse_cb, tb); + if (err < 0) + return err; + + if (tb[NFTA_INNER_HDRSIZE]) { + inner->hdrsize = + ntohl(mnl_attr_get_u32(tb[NFTA_INNER_HDRSIZE])); + e->flags |= (1 << NFTNL_EXPR_INNER_HDRSIZE); + } + if (tb[NFTA_INNER_FLAGS]) { + inner->flags = + ntohl(mnl_attr_get_u32(tb[NFTA_INNER_FLAGS])); + e->flags |= (1 << NFTNL_EXPR_INNER_FLAGS); + } + if (tb[NFTA_INNER_TYPE]) { + inner->type = + ntohl(mnl_attr_get_u32(tb[NFTA_INNER_TYPE])); + e->flags |= (1 << NFTNL_EXPR_INNER_TYPE); + } + if (tb[NFTA_INNER_EXPR]) { + expr = nftnl_expr_parse(tb[NFTA_INNER_EXPR]); + if (!expr) + return -1; + + if (inner->expr) + nftnl_expr_free(inner->expr); + + inner->expr = expr; + e->flags |= (1 << NFTNL_EXPR_INNER_EXPR); + } + + return 0; +} + +static int +nftnl_expr_inner_snprintf(char *buf, size_t remain, uint32_t flags, + const struct nftnl_expr *e) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + uint32_t offset = 0; + int ret; + + ret = snprintf(buf, remain, "type %u hdrsize %u flags %x [", + inner->type, inner->hdrsize, inner->flags); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = snprintf(buf + offset, remain, " %s ", inner->expr->ops->name); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = nftnl_expr_snprintf(buf + offset, remain, inner->expr, + NFTNL_OUTPUT_DEFAULT, 0); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = snprintf(buf + offset, remain, "] "); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + return offset; +} + +struct expr_ops expr_ops_inner = { + .name = "inner", + .alloc_len = sizeof(struct nftnl_expr_inner), + .max_attr = NFTA_INNER_MAX, + .free = nftnl_expr_inner_free, + .set = nftnl_expr_inner_set, + .get = nftnl_expr_inner_get, + .parse = nftnl_expr_inner_parse, + .build = nftnl_expr_inner_build, + .output = nftnl_expr_inner_snprintf, +}; diff --git a/src/expr/payload.c b/src/expr/payload.c index 88fff5f..c633e33 100644 --- a/src/expr/payload.c +++ b/src/expr/payload.c @@ -203,11 +203,12 @@ nftnl_expr_payload_parse(struct nftnl_expr *e, struct nlattr *attr) return 0; } -static const char *base2str_array[NFT_PAYLOAD_INNER_HEADER + 1] = { +static const char *base2str_array[NFT_PAYLOAD_TUN_HEADER + 1] = { [NFT_PAYLOAD_LL_HEADER] = "link", [NFT_PAYLOAD_NETWORK_HEADER] = "network", [NFT_PAYLOAD_TRANSPORT_HEADER] = "transport", [NFT_PAYLOAD_INNER_HEADER] = "inner", + [NFT_PAYLOAD_TUN_HEADER] = "tunnel", }; static const char *base2str(enum nft_payload_bases base) diff --git a/src/expr_ops.c b/src/expr_ops.c index 7248e4f..b85f472 100644 --- a/src/expr_ops.c +++ b/src/expr_ops.c @@ -14,6 +14,7 @@ extern struct expr_ops expr_ops_dup; extern struct expr_ops expr_ops_exthdr; extern struct expr_ops expr_ops_fwd; extern struct expr_ops expr_ops_immediate; +extern struct expr_ops expr_ops_inner; extern struct expr_ops expr_ops_last; extern struct expr_ops expr_ops_limit; extern struct expr_ops expr_ops_log; @@ -58,6 +59,7 @@ static struct expr_ops *expr_ops[] = { &expr_ops_exthdr, &expr_ops_fwd, &expr_ops_immediate, + &expr_ops_inner, &expr_ops_last, &expr_ops_limit, &expr_ops_log, -- cgit v1.2.3