From f9170d49b5af8bdbb762bb5f2abe9aa7cace3b9e Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Wed, 25 Nov 2015 16:50:19 +0000 Subject: payload: add payload statement Add support for payload mangling using the payload statement. The syntax is similar to the other data changing statements: nft filter output tcp dport set 25 Signed-off-by: Patrick McHardy --- include/linux/netfilter/nf_tables.h | 17 ++++++++++++++ include/statement.h | 11 +++++++++ src/evaluate.c | 25 ++++++++++++++++++-- src/netlink_delinearize.c | 46 ++++++++++++++++++++++++++++++++++--- src/netlink_linearize.c | 40 ++++++++++++++++++++++++++++++++ src/parser_bison.y | 9 ++++++++ src/payload.c | 24 +++++++++++++++++++ 7 files changed, 167 insertions(+), 5 deletions(-) diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h index 5ebe3d85..70a9619e 100644 --- a/include/linux/netfilter/nf_tables.h +++ b/include/linux/netfilter/nf_tables.h @@ -588,6 +588,17 @@ enum nft_payload_bases { NFT_PAYLOAD_TRANSPORT_HEADER, }; +/** + * enum nft_payload_csum_types - nf_tables payload expression checksum types + * + * @NFT_PAYLOAD_CSUM_NONE: no checksumming + * @NFT_PAYLOAD_CSUM_INET: internet checksum (RFC 791) + */ +enum nft_payload_csum_types { + NFT_PAYLOAD_CSUM_NONE, + NFT_PAYLOAD_CSUM_INET, +}; + /** * enum nft_payload_attributes - nf_tables payload expression netlink attributes * @@ -595,6 +606,9 @@ enum nft_payload_bases { * @NFTA_PAYLOAD_BASE: payload base (NLA_U32: nft_payload_bases) * @NFTA_PAYLOAD_OFFSET: payload offset relative to base (NLA_U32) * @NFTA_PAYLOAD_LEN: payload length (NLA_U32) + * @NFTA_PAYLOAD_SREG: source register to load data from (NLA_U32: nft_registers) + * @NFTA_PAYLOAD_CSUM_TYPE: checksum type (NLA_U32) + * @NFTA_PAYLOAD_CSUM_OFFSET: checksum offset relative to base (NLA_U32) */ enum nft_payload_attributes { NFTA_PAYLOAD_UNSPEC, @@ -602,6 +616,9 @@ enum nft_payload_attributes { NFTA_PAYLOAD_BASE, NFTA_PAYLOAD_OFFSET, NFTA_PAYLOAD_LEN, + NFTA_PAYLOAD_SREG, + NFTA_PAYLOAD_CSUM_TYPE, + NFTA_PAYLOAD_CSUM_OFFSET, __NFTA_PAYLOAD_MAX }; #define NFTA_PAYLOAD_MAX (__NFTA_PAYLOAD_MAX - 1) diff --git a/include/statement.h b/include/statement.h index 8b035d31..53620aec 100644 --- a/include/statement.h +++ b/include/statement.h @@ -17,6 +17,14 @@ struct counter_stmt { extern struct stmt *counter_stmt_alloc(const struct location *loc); +struct payload_stmt { + struct expr *expr; + struct expr *val; +}; + +extern struct stmt *payload_stmt_alloc(const struct location *loc, + struct expr *payload, struct expr *expr); + #include struct meta_stmt { enum nft_meta_keys key; @@ -128,6 +136,7 @@ extern struct stmt *set_stmt_alloc(const struct location *loc); * @STMT_EXPRESSION: expression statement (relational) * @STMT_VERDICT: verdict statement * @STMT_COUNTER: counters + * @STMT_PAYLOAD: payload statement * @STMT_META: meta statement * @STMT_LIMIT: limit statement * @STMT_LOG: log statement @@ -145,6 +154,7 @@ enum stmt_types { STMT_EXPRESSION, STMT_VERDICT, STMT_COUNTER, + STMT_PAYLOAD, STMT_META, STMT_LIMIT, STMT_LOG, @@ -196,6 +206,7 @@ struct stmt { union { struct expr *expr; struct counter_stmt counter; + struct payload_stmt payload; struct meta_stmt meta; struct log_stmt log; struct limit_stmt limit; diff --git a/src/evaluate.c b/src/evaluate.c index 48f071f7..7aab6aac 100644 --- a/src/evaluate.c +++ b/src/evaluate.c @@ -438,9 +438,9 @@ static bool resolve_protocol_conflict(struct eval_ctx *ctx, * generate the necessary relational expression and prepend it to the current * statement. */ -static int expr_evaluate_payload(struct eval_ctx *ctx, struct expr **expr) +static int __expr_evaluate_payload(struct eval_ctx *ctx, struct expr *expr) { - struct expr *payload = *expr; + struct expr *payload = expr; enum proto_bases base = payload->payload.base; struct stmt *nstmt; @@ -454,6 +454,14 @@ static int expr_evaluate_payload(struct eval_ctx *ctx, struct expr **expr) ctx->pctx.protocol[base].desc->name, payload->payload.desc->name); + return 0; +} + +static int expr_evaluate_payload(struct eval_ctx *ctx, struct expr **expr) +{ + if (__expr_evaluate_payload(ctx, *expr) < 0) + return -1; + return expr_evaluate_primary(ctx, expr); } @@ -1353,6 +1361,17 @@ static int stmt_evaluate_verdict(struct eval_ctx *ctx, struct stmt *stmt) return 0; } +static int stmt_evaluate_payload(struct eval_ctx *ctx, struct stmt *stmt) +{ + if (__expr_evaluate_payload(ctx, stmt->payload.expr) < 0) + return -1; + + return stmt_evaluate_arg(ctx, stmt, + stmt->payload.expr->dtype, + stmt->payload.expr->len, + &stmt->payload.val); +} + static int stmt_evaluate_meta(struct eval_ctx *ctx, struct stmt *stmt) { return stmt_evaluate_arg(ctx, stmt, @@ -1916,6 +1935,8 @@ int stmt_evaluate(struct eval_ctx *ctx, struct stmt *stmt) return stmt_evaluate_expr(ctx, stmt); case STMT_VERDICT: return stmt_evaluate_verdict(ctx, stmt); + case STMT_PAYLOAD: + return stmt_evaluate_payload(ctx, stmt); case STMT_META: return stmt_evaluate_meta(ctx, stmt); case STMT_CT: diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c index 3499d748..614fbe00 100644 --- a/src/netlink_delinearize.c +++ b/src/netlink_delinearize.c @@ -397,9 +397,9 @@ static void netlink_parse_byteorder(struct netlink_parse_ctx *ctx, netlink_set_register(ctx, dreg, expr); } -static void netlink_parse_payload(struct netlink_parse_ctx *ctx, - const struct location *loc, - const struct nftnl_expr *nle) +static void netlink_parse_payload_expr(struct netlink_parse_ctx *ctx, + const struct location *loc, + const struct nftnl_expr *nle) { enum nft_registers dreg; uint32_t base, offset, len; @@ -416,6 +416,39 @@ static void netlink_parse_payload(struct netlink_parse_ctx *ctx, netlink_set_register(ctx, dreg, expr); } +static void netlink_parse_payload_stmt(struct netlink_parse_ctx *ctx, + const struct location *loc, + const struct nftnl_expr *nle) +{ + enum nft_registers sreg; + uint32_t base, offset, len; + struct expr *expr, *val; + struct stmt *stmt; + + base = nftnl_expr_get_u32(nle, NFTNL_EXPR_PAYLOAD_BASE) + 1; + offset = nftnl_expr_get_u32(nle, NFTNL_EXPR_PAYLOAD_OFFSET) * BITS_PER_BYTE; + len = nftnl_expr_get_u32(nle, NFTNL_EXPR_PAYLOAD_LEN) * BITS_PER_BYTE; + + expr = payload_expr_alloc(loc, NULL, 0); + payload_init_raw(expr, base, offset, len); + + sreg = netlink_parse_register(nle, NFT_EXPR_PAYLOAD_SREG); + val = netlink_get_register(ctx, loc, sreg); + stmt = payload_stmt_alloc(loc, expr, val); + + list_add_tail(&stmt->list, &ctx->rule->stmts); +} + +static void netlink_parse_payload(struct netlink_parse_ctx *ctx, + const struct location *loc, + const struct nftnl_expr *nle) +{ + if (nftnl_expr_is_set(nle, NFT_EXPR_PAYLOAD_DREG)) + netlink_parse_payload_expr(ctx, loc, nle); + else + netlink_parse_payload_stmt(ctx, loc, nle); +} + static void netlink_parse_exthdr(struct netlink_parse_ctx *ctx, const struct location *loc, const struct nftnl_expr *nle) @@ -1554,6 +1587,13 @@ static void rule_parse_postprocess(struct netlink_parse_ctx *ctx, struct rule *r case STMT_EXPRESSION: stmt_expr_postprocess(&rctx, prev); break; + case STMT_PAYLOAD: + expr_postprocess(&rctx, &stmt->payload.expr); + expr_set_type(stmt->payload.val, + stmt->payload.expr->dtype, + stmt->payload.expr->byteorder); + expr_postprocess(&rctx, &stmt->payload.val); + break; case STMT_META: if (stmt->meta.expr != NULL) expr_postprocess(&rctx, &stmt->meta.expr); diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c index 7c6ef165..3c8f4ca9 100644 --- a/src/netlink_linearize.c +++ b/src/netlink_linearize.c @@ -680,6 +680,44 @@ static void netlink_gen_counter_stmt(struct netlink_linearize_ctx *ctx, nftnl_rule_add_expr(ctx->nlr, nle); } +static void netlink_gen_payload_stmt(struct netlink_linearize_ctx *ctx, + const struct stmt *stmt) +{ + struct nftnl_expr *nle; + const struct proto_desc *desc; + const struct expr *expr; + enum nft_registers sreg; + unsigned int csum_off; + + sreg = get_register(ctx, stmt->payload.val); + netlink_gen_expr(ctx, stmt->payload.val, sreg); + release_register(ctx, stmt->payload.val); + + expr = stmt->payload.expr; + + csum_off = 0; + desc = expr->payload.desc; + if (desc != NULL && desc->checksum_key) + csum_off = desc->templates[desc->checksum_key].offset; + + nle = alloc_nft_expr("payload"); + netlink_put_register(nle, NFTNL_EXPR_PAYLOAD_SREG, sreg); + nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_BASE, + expr->payload.base - 1); + nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_OFFSET, + expr->payload.offset / BITS_PER_BYTE); + nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_LEN, + expr->len / BITS_PER_BYTE); + if (csum_off) { + nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_CSUM_TYPE, + NFT_PAYLOAD_CSUM_INET); + nftnl_expr_set_u32(nle, NFTNL_EXPR_PAYLOAD_CSUM_OFFSET, + csum_off / BITS_PER_BYTE); + } + + nftnl_rule_add_expr(ctx->nlr, nle); +} + static void netlink_gen_meta_stmt(struct netlink_linearize_ctx *ctx, const struct stmt *stmt) { @@ -990,6 +1028,8 @@ static void netlink_gen_stmt(struct netlink_linearize_ctx *ctx, return netlink_gen_verdict_stmt(ctx, stmt); case STMT_COUNTER: return netlink_gen_counter_stmt(ctx, stmt); + case STMT_PAYLOAD: + return netlink_gen_payload_stmt(ctx, stmt); case STMT_META: return netlink_gen_meta_stmt(ctx, stmt); case STMT_LOG: diff --git a/src/parser_bison.y b/src/parser_bison.y index ec1e7428..fbfe7eaf 100644 --- a/src/parser_bison.y +++ b/src/parser_bison.y @@ -447,6 +447,8 @@ static void location_update(struct location *loc, struct location *rhs, int n) %destructor { stmt_free($$); } stmt match_stmt verdict_stmt %type counter_stmt counter_stmt_alloc %destructor { stmt_free($$); } counter_stmt counter_stmt_alloc +%type payload_stmt +%destructor { stmt_free($$); } payload_stmt %type ct_stmt %destructor { stmt_free($$); } ct_stmt %type meta_stmt @@ -1312,6 +1314,7 @@ stmt_list : stmt stmt : verdict_stmt | match_stmt | counter_stmt + | payload_stmt | meta_stmt | log_stmt | limit_stmt @@ -2061,6 +2064,12 @@ ct_stmt : CT ct_key SET expr } ; +payload_stmt : payload_expr SET expr + { + $$ = payload_stmt_alloc(&@$, $1, $3); + } + ; + payload_expr : payload_raw_expr | eth_hdr_expr | vlan_hdr_expr diff --git a/src/payload.c b/src/payload.c index b75527a1..a97041e1 100644 --- a/src/payload.c +++ b/src/payload.c @@ -138,6 +138,30 @@ void payload_init_raw(struct expr *expr, enum proto_bases base, expr->len = len; } +static void payload_stmt_print(const struct stmt *stmt) +{ + expr_print(stmt->payload.expr); + printf(" set "); + expr_print(stmt->payload.val); +} + +static const struct stmt_ops payload_stmt_ops = { + .type = STMT_PAYLOAD, + .name = "payload", + .print = payload_stmt_print, +}; + +struct stmt *payload_stmt_alloc(const struct location *loc, + struct expr *expr, struct expr *val) +{ + struct stmt *stmt; + + stmt = stmt_alloc(loc, &payload_stmt_ops); + stmt->payload.expr = expr; + stmt->payload.val = val; + return stmt; +} + /** * payload_gen_dependency - generate match expression on payload dependency * -- cgit v1.2.3