From 00c179b4c9f9f9394cc6f79e5f2a68410631fd72 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 3 Aug 2012 17:31:48 +0200 Subject: initial version of libnftables It adds support for table, chain and rule handling. This also includes expression handling for each rule. Signed-off-by: Pablo Neira Ayuso --- src/expr/payload.c | 185 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 185 insertions(+) create mode 100644 src/expr/payload.c (limited to 'src/expr/payload.c') diff --git a/src/expr/payload.c b/src/expr/payload.c new file mode 100644 index 0000000..746a127 --- /dev/null +++ b/src/expr/payload.c @@ -0,0 +1,185 @@ +/* + * (C) 2012 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. + * + * This code has been sponsored by Sophos Astaro + */ + +#include "internal.h" + +#include +#include +#include + +#include + +#include + +#include + +#include "expr_ops.h" + +struct nft_expr_payload { + enum nft_registers dreg; + enum nft_payload_bases base; + unsigned int offset; + unsigned int len; +}; + +static int +nft_rule_expr_payload_set(struct nft_rule_expr *e, uint16_t type, + const void *data, size_t data_len) +{ + struct nft_expr_payload *payload = (struct nft_expr_payload *)e->data; + + switch(type) { + case NFT_EXPR_PAYLOAD_DREG: + payload->dreg = *((uint32_t *)data); + break; + case NFT_EXPR_PAYLOAD_BASE: + payload->base = *((uint32_t *)data); + break; + case NFT_EXPR_PAYLOAD_OFFSET: + payload->offset = *((unsigned int *)data); + break; + case NFT_EXPR_PAYLOAD_LEN: + payload->len = *((unsigned int *)data); + break; + default: + return -1; + } + return 0; +} + +static const void * +nft_rule_expr_payload_get(struct nft_rule_expr *e, uint16_t type, size_t *data_len) +{ + struct nft_expr_payload *payload = (struct nft_expr_payload *)e->data; + + switch(type) { + case NFT_EXPR_PAYLOAD_DREG: + if (e->flags & (1 << NFT_EXPR_PAYLOAD_DREG)) { + *data_len = sizeof(payload->dreg); + return &payload->dreg; + } else + return NULL; + break; + case NFT_EXPR_PAYLOAD_BASE: + if (e->flags & (1 << NFT_EXPR_PAYLOAD_BASE)) { + *data_len = sizeof(payload->base); + return &payload->base; + } else + return NULL; + break; + case NFT_EXPR_PAYLOAD_OFFSET: + if (e->flags & (1 << NFT_EXPR_PAYLOAD_OFFSET)) { + *data_len = sizeof(payload->offset); + return &payload->offset; + } else + return NULL; + break; + case NFT_EXPR_PAYLOAD_LEN: + if (e->flags & (1 << NFT_EXPR_PAYLOAD_LEN)) { + *data_len = sizeof(payload->len); + return &payload->len; + } else + return NULL; + break; + default: + break; + } + return NULL; +} + +static int nft_rule_expr_payload_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_PAYLOAD_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_PAYLOAD_DREG: + case NFTA_PAYLOAD_BASE: + case NFTA_PAYLOAD_OFFSET: + case NFTA_PAYLOAD_LEN: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nft_rule_expr_payload_build(struct nlmsghdr *nlh, struct nft_rule_expr *e) +{ + struct nft_expr_payload *payload = (struct nft_expr_payload *)e->data; + + if (e->flags & (1 << NFT_EXPR_PAYLOAD_DREG)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_DREG, htonl(payload->dreg)); + if (e->flags & (1 << NFT_EXPR_PAYLOAD_BASE)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_BASE, htonl(payload->base)); + if (e->flags & (1 << NFT_EXPR_PAYLOAD_OFFSET)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_OFFSET, htonl(payload->offset)); + if (e->flags & (1 << NFT_EXPR_PAYLOAD_LEN)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_LEN, htonl(payload->len)); +} + +static int +nft_rule_expr_payload_parse(struct nft_rule_expr *e, struct nlattr *attr) +{ + struct nft_expr_payload *payload = (struct nft_expr_payload *)e->data; + struct nlattr *tb[NFTA_PAYLOAD_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nft_rule_expr_payload_cb, tb) < 0) + return -1; + + if (tb[NFTA_PAYLOAD_DREG]) { + payload->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_DREG])); + e->flags |= (1 << NFT_EXPR_PAYLOAD_DREG); + } + if (tb[NFTA_PAYLOAD_BASE]) { + payload->base = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_BASE])); + e->flags |= (1 << NFT_EXPR_PAYLOAD_BASE); + } + if (tb[NFTA_PAYLOAD_OFFSET]) { + payload->offset = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_OFFSET])); + e->flags |= (1 << NFT_EXPR_PAYLOAD_OFFSET); + } + if (tb[NFTA_PAYLOAD_LEN]) { + payload->len = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_LEN])); + e->flags |= (1 << NFT_EXPR_PAYLOAD_LEN); + } + + return 0; +} + +static int +nft_rule_expr_payload_snprintf(char *buf, size_t len, struct nft_rule_expr *e) +{ + struct nft_expr_payload *payload = (struct nft_expr_payload *)e->data; + + return snprintf(buf, len, "dreg=%u base=%u offset=%u len=%u ", + payload->dreg, payload->base, + payload->offset, payload->len); +} + +struct expr_ops expr_ops_payload = { + .name = "payload", + .alloc_len = sizeof(struct nft_expr_payload), + .max_attr = NFTA_PAYLOAD_MAX, + .set = nft_rule_expr_payload_set, + .get = nft_rule_expr_payload_get, + .parse = nft_rule_expr_payload_parse, + .build = nft_rule_expr_payload_build, + .snprintf = nft_rule_expr_payload_snprintf, +}; -- cgit v1.2.3