From 1ebd1e974e95ea90389064265523840968f50859 Mon Sep 17 00:00:00 2001 From: Laura Garcia Liebana Date: Thu, 23 Feb 2017 12:11:08 +0100 Subject: expr: hash: support of symmetric hash This patch provides symmetric hash support according to source ip address and port, and destination ip address and port. The new attribute NFTA_HASH_TYPE has been included to support different types of hashing functions. Currently supported NFT_HASH_JENKINS through jhash and NFT_HASH_SYM through symhash. The main difference between both types are: - jhash requires an expression with sreg, symhash doesn't. - symhash supports modulus and offset, but not seed. Examples: nft add rule ip nat prerouting ct mark set jhash ip saddr mod 2 nft add rule ip nat prerouting ct mark set symhash mod 2 Signed-off-by: Laura Garcia Liebana Signed-off-by: Pablo Neira Ayuso --- include/libnftnl/expr.h | 1 + include/linux/netfilter/nf_tables.h | 13 +++++++++++ src/expr/hash.c | 46 ++++++++++++++++++++++++++++++++----- tests/nft-expr_hash-test.c | 4 ++++ 4 files changed, 58 insertions(+), 6 deletions(-) diff --git a/include/libnftnl/expr.h b/include/libnftnl/expr.h index 7d327ea..b06d1b1 100644 --- a/include/libnftnl/expr.h +++ b/include/libnftnl/expr.h @@ -229,6 +229,7 @@ enum { NFTNL_EXPR_HASH_MODULUS, NFTNL_EXPR_HASH_SEED, NFTNL_EXPR_HASH_OFFSET, + NFTNL_EXPR_HASH_TYPE, }; enum { diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h index 05215d3..4f7d756 100644 --- a/include/linux/netfilter/nf_tables.h +++ b/include/linux/netfilter/nf_tables.h @@ -815,6 +815,17 @@ enum nft_rt_keys { NFT_RT_NEXTHOP6, }; +/** + * enum nft_hash_types - nf_tables hash expression types + * + * @NFT_HASH_JENKINS: Jenkins Hash + * @NFT_HASH_SYM: Symmetric Hash + */ +enum nft_hash_types { + NFT_HASH_JENKINS, + NFT_HASH_SYM, +}; + /** * enum nft_hash_attributes - nf_tables hash expression netlink attributes * @@ -824,6 +835,7 @@ enum nft_rt_keys { * @NFTA_HASH_MODULUS: modulus value (NLA_U32) * @NFTA_HASH_SEED: seed value (NLA_U32) * @NFTA_HASH_OFFSET: add this offset value to hash result (NLA_U32) + * @NFTA_HASH_TYPE: hash operation (NLA_U32: nft_hash_types) */ enum nft_hash_attributes { NFTA_HASH_UNSPEC, @@ -833,6 +845,7 @@ enum nft_hash_attributes { NFTA_HASH_MODULUS, NFTA_HASH_SEED, NFTA_HASH_OFFSET, + NFTA_HASH_TYPE, __NFTA_HASH_MAX, }; #define NFTA_HASH_MAX (__NFTA_HASH_MAX - 1) diff --git a/src/expr/hash.c b/src/expr/hash.c index 83f9317..d870510 100644 --- a/src/expr/hash.c +++ b/src/expr/hash.c @@ -21,6 +21,7 @@ #include struct nftnl_expr_hash { + enum nft_hash_types type; enum nft_registers sreg; enum nft_registers dreg; unsigned int len; @@ -34,7 +35,6 @@ nftnl_expr_hash_set(struct nftnl_expr *e, uint16_t type, const void *data, uint32_t data_len) { struct nftnl_expr_hash *hash = nftnl_expr_data(e); - switch (type) { case NFTNL_EXPR_HASH_SREG: hash->sreg = *((uint32_t *)data); @@ -54,6 +54,9 @@ nftnl_expr_hash_set(struct nftnl_expr *e, uint16_t type, case NFTNL_EXPR_HASH_OFFSET: hash->offset = *((uint32_t *)data); break; + case NFTNL_EXPR_HASH_TYPE: + hash->type = *((uint32_t *)data); + break; default: return -1; } @@ -85,6 +88,9 @@ nftnl_expr_hash_get(const struct nftnl_expr *e, uint16_t type, case NFTNL_EXPR_HASH_OFFSET: *data_len = sizeof(hash->offset); return &hash->offset; + case NFTNL_EXPR_HASH_TYPE: + *data_len = sizeof(hash->type); + return &hash->type; } return NULL; } @@ -104,6 +110,7 @@ static int nftnl_expr_hash_cb(const struct nlattr *attr, void *data) case NFTA_HASH_MODULUS: case NFTA_HASH_SEED: case NFTA_HASH_OFFSET: + case NFTA_HASH_TYPE: if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) abi_breakage(); break; @@ -130,6 +137,8 @@ nftnl_expr_hash_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) mnl_attr_put_u32(nlh, NFTA_HASH_SEED, htonl(hash->seed)); if (e->flags & (1 << NFTNL_EXPR_HASH_OFFSET)) mnl_attr_put_u32(nlh, NFTA_HASH_OFFSET, htonl(hash->offset)); + if (e->flags & (1 << NFTNL_EXPR_HASH_TYPE)) + mnl_attr_put_u32(nlh, NFTA_HASH_TYPE, htonl(hash->type)); } static int @@ -166,6 +175,10 @@ nftnl_expr_hash_parse(struct nftnl_expr *e, struct nlattr *attr) hash->offset = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_OFFSET])); e->flags |= (1 << NFTNL_EXPR_HASH_OFFSET); } + if (tb[NFTA_HASH_TYPE]) { + hash->type = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_TYPE])); + e->flags |= (1 << NFTNL_EXPR_HASH_TYPE); + } return ret; } @@ -174,7 +187,7 @@ static int nftnl_expr_hash_json_parse(struct nftnl_expr *e, json_t *root, struct nftnl_parse_err *err) { #ifdef JSON_PARSING - uint32_t sreg, dreg, len, modulus, seed, offset; + uint32_t sreg, dreg, len, modulus, seed, offset, type; if (nftnl_jansson_parse_reg(root, "sreg", NFTNL_TYPE_U32, &sreg, err) == 0) @@ -200,6 +213,10 @@ static int nftnl_expr_hash_json_parse(struct nftnl_expr *e, json_t *root, &offset, err) == 0) nftnl_expr_set_u32(e, NFTNL_EXPR_HASH_OFFSET, offset); + if (nftnl_jansson_parse_val(root, "type", NFTNL_TYPE_U32, + &type, err) == 0) + nftnl_expr_set_u32(e, NFTNL_EXPR_HASH_TYPE, type); + return 0; #else errno = EOPNOTSUPP; @@ -214,10 +231,23 @@ nftnl_expr_hash_snprintf_default(char *buf, size_t size, struct nftnl_expr_hash *hash = nftnl_expr_data(e); int len = size, offset = 0, ret; - ret = snprintf(buf, len, "reg %u = jhash(reg %u, %u, 0x%x) %% mod %u ", - hash->dreg, hash->sreg, hash->len, hash->seed, - hash->modulus); - SNPRINTF_BUFFER_SIZE(ret, size, len, offset); + switch (hash->type) { + case NFT_HASH_SYM: + ret = + snprintf(buf, len, "reg %u = symhash() %% mod %u ", hash->dreg, + hash->modulus); + SNPRINTF_BUFFER_SIZE(ret, size, len, offset); + break; + case NFT_HASH_JENKINS: + default: + ret = + snprintf(buf, len, + "reg %u = jhash(reg %u, %u, 0x%x) %% mod %u ", + hash->dreg, hash->sreg, hash->len, hash->seed, + hash->modulus); + SNPRINTF_BUFFER_SIZE(ret, size, len, offset); + break; + } if (hash->offset) { ret = snprintf(buf + offset, len, "offset %u ", hash->offset); @@ -246,6 +276,8 @@ static int nftnl_expr_hash_export(char *buf, size_t size, nftnl_buf_u32(&b, type, hash->seed, SEED); if (e->flags & (1 << NFTNL_EXPR_HASH_OFFSET)) nftnl_buf_u32(&b, type, hash->offset, OFFSET); + if (e->flags & (1 << NFTNL_EXPR_HASH_TYPE)) + nftnl_buf_u32(&b, type, hash->type, TYPE); return nftnl_buf_done(&b); } @@ -285,6 +317,8 @@ static bool nftnl_expr_hash_cmp(const struct nftnl_expr *e1, eq &= (h1->seed == h2->seed); if (e1->flags & (1 << NFTNL_EXPR_HASH_OFFSET)) eq &= (h1->offset == h2->offset); + if (e1->flags & (1 << NFTNL_EXPR_HASH_TYPE)) + eq &= (h1->type == h2->type); return eq; } diff --git a/tests/nft-expr_hash-test.c b/tests/nft-expr_hash-test.c index d928234..7be6e9e 100644 --- a/tests/nft-expr_hash-test.c +++ b/tests/nft-expr_hash-test.c @@ -45,6 +45,9 @@ static void cmp_nftnl_expr(struct nftnl_expr *rule_a, if (nftnl_expr_get_u32(rule_a, NFTNL_EXPR_HASH_OFFSET) != nftnl_expr_get_u32(rule_b, NFTNL_EXPR_HASH_OFFSET)) print_err("Expr NFTNL_EXPR_HASH_OFFSET mismatches"); + if (nftnl_expr_get_u32(rule_a, NFTNL_EXPR_HASH_TYPE) != + nftnl_expr_get_u32(rule_b, NFTNL_EXPR_HASH_TYPE)) + print_err("Expr NFTNL_EXPR_HASH_TYPE mismatches"); } int main(int argc, char *argv[]) @@ -69,6 +72,7 @@ int main(int argc, char *argv[]) nftnl_expr_set_u32(ex, NFTNL_EXPR_HASH_MODULUS, 0x78123456); nftnl_expr_set_u32(ex, NFTNL_EXPR_HASH_SEED, 0x78123456); nftnl_expr_set_u32(ex, NFTNL_EXPR_HASH_OFFSET, 0x3612845); + nftnl_expr_set_u32(ex, NFTNL_EXPR_HASH_TYPE, NFT_HASH_JENKINS); nftnl_rule_add_expr(a, ex); -- cgit v1.2.3