From 038d226f2e6cc132de151cc295ea2e4b8805659a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?M=C3=A1t=C3=A9=20Eckl?= Date: Mon, 28 May 2018 09:15:32 +0200 Subject: src: Add support for native socket matching MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Máté Eckl Signed-off-by: Pablo Neira Ayuso --- include/libnftnl/expr.h | 5 + include/linux/netfilter/nf_tables.h | 25 +++++ src/Makefile.am | 1 + src/expr/socket.c | 208 ++++++++++++++++++++++++++++++++++++ src/expr_ops.c | 2 + 5 files changed, 241 insertions(+) create mode 100644 src/expr/socket.c diff --git a/include/libnftnl/expr.h b/include/libnftnl/expr.h index 45ff533..3dcd7dc 100644 --- a/include/libnftnl/expr.h +++ b/include/libnftnl/expr.h @@ -72,6 +72,11 @@ enum { NFTNL_EXPR_RT_DREG, }; +enum { + NFTNL_EXPR_SOCKET_KEY = NFTNL_EXPR_BASE, + NFTNL_EXPR_SOCKET_DREG, +}; + enum { NFTNL_EXPR_CMP_SREG = NFTNL_EXPR_BASE, NFTNL_EXPR_CMP_OP, diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h index 660168a..db80d53 100644 --- a/include/linux/netfilter/nf_tables.h +++ b/include/linux/netfilter/nf_tables.h @@ -904,6 +904,31 @@ enum nft_rt_attributes { }; #define NFTA_RT_MAX (__NFTA_RT_MAX - 1) +/** + * enum nft_socket_attributes - nf_tables socket expression netlink attributes + * + * @NFTA_SOCKET_KEY: socket key to match + * @NFTA_SOCKET_DREG: destination register + */ +enum nft_socket_attributes { + NFTA_SOCKET_UNSPEC, + NFTA_SOCKET_KEY, + NFTA_SOCKET_DREG, + __NFTA_SOCKET_MAX +}; +#define NFTA_SOCKET_MAX (__NFTA_SOCKET_MAX - 1) + +/* + * enum nft_socket_keys - nf_tables socket expression keys + * + * @NFT_SOCKET_TRANSPARENT: Value of the IP(V6)_TRANSPARENT socket option_ + */ +enum nft_socket_keys { + NFT_SOCKET_TRANSPARENT, + __NFT_SOCKET_MAX +}; +#define NFT_SOCKET_MAX (__NFT_SOCKET_MAX - 1) + /** * enum nft_ct_keys - nf_tables ct expression keys * diff --git a/src/Makefile.am b/src/Makefile.am index 578b7d3..cd06372 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -54,6 +54,7 @@ libnftnl_la_SOURCES = utils.c \ expr/masq.c \ expr/redir.c \ expr/hash.c \ + expr/socket.c \ obj/counter.c \ obj/ct_helper.c \ obj/quota.c \ diff --git a/src/expr/socket.c b/src/expr/socket.c new file mode 100644 index 0000000..db160a1 --- /dev/null +++ b/src/expr/socket.c @@ -0,0 +1,208 @@ +/* + * Copyright (c) 2018 Máté Eckl + * + * 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 +#include +#include +#include +#include +#include + +#include "internal.h" +#include +#include +#include + +struct nftnl_expr_socket { + enum nft_socket_keys key; + enum nft_registers dreg; +}; + +static int +nftnl_expr_socket_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_socket *socket = nftnl_expr_data(e); + + switch (type) { + case NFTNL_EXPR_SOCKET_KEY: + socket->key = *((uint32_t *)data); + break; + case NFTNL_EXPR_SOCKET_DREG: + socket->dreg = *((uint32_t *)data); + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_socket_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_socket *socket = nftnl_expr_data(e); + + switch (type) { + case NFTNL_EXPR_SOCKET_KEY: + *data_len = sizeof(socket->key); + return &socket->key; + case NFTNL_EXPR_SOCKET_DREG: + *data_len = sizeof(socket->dreg); + return &socket->dreg; + } + return NULL; +} + +static int nftnl_expr_socket_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_SOCKET_MAX) < 0) + return MNL_CB_OK; + + switch (type) { + case NFTA_SOCKET_KEY: + case NFTA_SOCKET_DREG: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_socket_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_socket *socket = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_SOCKET_KEY)) + mnl_attr_put_u32(nlh, NFTA_SOCKET_KEY, htonl(socket->key)); + if (e->flags & (1 << NFTNL_EXPR_SOCKET_DREG)) + mnl_attr_put_u32(nlh, NFTA_SOCKET_DREG, htonl(socket->dreg)); +} + +static int +nftnl_expr_socket_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_socket *socket = nftnl_expr_data(e); + struct nlattr *tb[NFTA_SOCKET_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nftnl_expr_socket_cb, tb) < 0) + return -1; + + if (tb[NFTA_SOCKET_KEY]) { + socket->key = ntohl(mnl_attr_get_u32(tb[NFTA_SOCKET_KEY])); + e->flags |= (1 << NFTNL_EXPR_SOCKET_KEY); + } + if (tb[NFTA_SOCKET_DREG]) { + socket->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_SOCKET_DREG])); + e->flags |= (1 << NFTNL_EXPR_SOCKET_DREG); + } + + return 0; +} + +static const char *socket_key2str_array[NFT_SOCKET_MAX + 1] = { + [NFT_SOCKET_TRANSPARENT] = "transparent", +}; + +static const char *socket_key2str(uint8_t key) +{ + if (key < NFT_SOCKET_MAX + 1) + return socket_key2str_array[key]; + + return "unknown"; +} + +static inline int str2socket_key(const char *str) +{ + int i; + + for (i = 0; i < NFT_SOCKET_MAX + 1; i++) { + if (strcmp(str, socket_key2str_array[i]) == 0) + return i; + } + + errno = EINVAL; + return -1; +} + +static int +nftnl_expr_socket_snprintf_default(char *buf, size_t len, + const struct nftnl_expr *e) +{ + struct nftnl_expr_socket *socket = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_SOCKET_DREG)) { + return snprintf(buf, len, "load %s => reg %u ", + socket_key2str(socket->key), socket->dreg); + } + return 0; +} + +static int nftnl_expr_socket_export(char *buf, size_t size, + const struct nftnl_expr *e, int type) +{ + struct nftnl_expr_socket *socket = nftnl_expr_data(e); + NFTNL_BUF_INIT(b, buf, size); + + if (e->flags & (1 << NFTNL_EXPR_SOCKET_DREG)) + nftnl_buf_u32(&b, type, socket->dreg, DREG); + if (e->flags & (1 << NFTNL_EXPR_SOCKET_KEY)) + nftnl_buf_str(&b, type, socket_key2str(socket->key), KEY); + + return nftnl_buf_done(&b); +} + +static int +nftnl_expr_socket_snprintf(char *buf, size_t len, uint32_t type, + uint32_t flags, const struct nftnl_expr *e) +{ + switch (type) { + case NFTNL_OUTPUT_DEFAULT: + return nftnl_expr_socket_snprintf_default(buf, len, e); + case NFTNL_OUTPUT_XML: + case NFTNL_OUTPUT_JSON: + return nftnl_expr_socket_export(buf, len, e, type); + default: + break; + } + return -1; +} + +static bool nftnl_expr_socket_cmp(const struct nftnl_expr *e1, + const struct nftnl_expr *e2) +{ + struct nftnl_expr_socket *r1 = nftnl_expr_data(e1); + struct nftnl_expr_socket *r2 = nftnl_expr_data(e2); + bool eq = true; + + if (e1->flags & (1 << NFTNL_EXPR_SOCKET_KEY)) + eq &= (r1->key == r2->key); + if (e1->flags & (1 << NFTNL_EXPR_SOCKET_DREG)) + eq &= (r1->dreg == r2->dreg); + + return eq; +} + +struct expr_ops expr_ops_socket = { + .name = "socket", + .alloc_len = sizeof(struct nftnl_expr_socket), + .max_attr = NFTA_SOCKET_MAX, + .cmp = nftnl_expr_socket_cmp, + .set = nftnl_expr_socket_set, + .get = nftnl_expr_socket_get, + .parse = nftnl_expr_socket_parse, + .build = nftnl_expr_socket_build, + .snprintf = nftnl_expr_socket_snprintf, +}; diff --git a/src/expr_ops.c b/src/expr_ops.c index 041bd35..9df55fd 100644 --- a/src/expr_ops.c +++ b/src/expr_ops.c @@ -34,6 +34,7 @@ extern struct expr_ops expr_ops_dynset; extern struct expr_ops expr_ops_hash; extern struct expr_ops expr_ops_fib; extern struct expr_ops expr_ops_flow; +extern struct expr_ops expr_ops_socket; static struct expr_ops expr_ops_notrack = { .name = "notrack", @@ -71,6 +72,7 @@ static struct expr_ops *expr_ops[] = { &expr_ops_fib, &expr_ops_objref, &expr_ops_flow, + &expr_ops_socket, NULL, }; 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