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/cmp.c | 194 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 194 insertions(+) create mode 100644 src/expr/cmp.c (limited to 'src/expr/cmp.c') diff --git a/src/expr/cmp.c b/src/expr/cmp.c new file mode 100644 index 0000000..cabaddd --- /dev/null +++ b/src/expr/cmp.c @@ -0,0 +1,194 @@ +/* + * (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 +#include "expr_ops.h" +#include "data_reg.h" + +struct nft_expr_cmp { + union nft_data_reg data; + uint8_t sreg; /* enum nft_registers */ + uint8_t op; /* enum nft_cmp_ops */ +}; + +static int +nft_rule_expr_cmp_set(struct nft_rule_expr *e, uint16_t type, + const void *data, size_t data_len) +{ + struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data; + + switch(type) { + case NFT_EXPR_CMP_SREG: + cmp->sreg = *((uint32_t *)data); + break; + case NFT_EXPR_CMP_OP: + cmp->op = *((uint32_t *)data); + break; + case NFT_EXPR_CMP_DATA: + memcpy(&cmp->data.val, data, data_len); + cmp->data.len = data_len; + break; + default: + return -1; + } + return 0; +} + +static const void * +nft_rule_expr_cmp_get(struct nft_rule_expr *e, uint16_t type, size_t *data_len) +{ + struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data; + + switch(type) { + case NFT_EXPR_CMP_SREG: + if (e->flags & (1 << NFT_EXPR_CMP_SREG)) { + *data_len = sizeof(cmp->sreg); + return &cmp->sreg; + } else + return NULL; + break; + case NFT_EXPR_CMP_OP: + if (e->flags & (1 << NFT_EXPR_CMP_OP)) { + *data_len = sizeof(cmp->op); + return &cmp->op; + } else + return NULL; + break; + case NFT_EXPR_CMP_DATA: + if (e->flags & (1 << NFT_EXPR_CMP_DATA)) { + *data_len = cmp->data.len; + return &cmp->data.val; + } else + return NULL; + break; + default: + break; + } + return NULL; +} + +static int nft_rule_expr_cmp_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_CMP_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_CMP_SREG: + case NFTA_CMP_OP: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + case NFTA_CMP_DATA: + if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nft_rule_expr_cmp_build(struct nlmsghdr *nlh, struct nft_rule_expr *e) +{ + struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data; + + if (e->flags & (1 << NFT_EXPR_CMP_SREG)) + mnl_attr_put_u32(nlh, NFTA_CMP_SREG, htonl(cmp->sreg)); + if (e->flags & (1 << NFT_EXPR_CMP_OP)) + mnl_attr_put_u32(nlh, NFTA_CMP_OP, htonl(cmp->op)); + if (e->flags & (1 << NFT_EXPR_CMP_DATA)) { + struct nlattr *nest; + + nest = mnl_attr_nest_start(nlh, NFTA_CMP_DATA); + mnl_attr_put(nlh, NFTA_DATA_VALUE, cmp->data.len, cmp->data.val); + mnl_attr_nest_end(nlh, nest); + } +} + +static int +nft_rule_expr_cmp_parse(struct nft_rule_expr *e, struct nlattr *attr) +{ + struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data; + struct nlattr *tb[NFTA_CMP_MAX+1] = {}; + int ret = 0; + + if (mnl_attr_parse_nested(attr, nft_rule_expr_cmp_cb, tb) < 0) + return -1; + + if (tb[NFTA_CMP_SREG]) { + cmp->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_CMP_SREG])); + e->flags |= (1 << NFTA_CMP_SREG); + } + if (tb[NFTA_CMP_OP]) { + cmp->op = ntohl(mnl_attr_get_u32(tb[NFTA_CMP_OP])); + e->flags |= (1 << NFTA_CMP_OP); + } + if (tb[NFTA_CMP_DATA]) { + ret = nft_parse_data(&cmp->data, tb[NFTA_CMP_DATA], NULL); + e->flags |= (1 << NFTA_CMP_DATA); + } + + return ret; +} + +static char *expr_cmp_str[] = { + [NFT_CMP_EQ] = "eq", + [NFT_CMP_NEQ] = "neq", + [NFT_CMP_LT] = "lt", + [NFT_CMP_LTE] = "lte", + [NFT_CMP_GT] = "gt", + [NFT_CMP_GTE] = "gte", +}; + +static int +nft_rule_expr_cmp_snprintf(char *buf, size_t size, struct nft_rule_expr *e) +{ + struct nft_expr_cmp *cmp = (struct nft_expr_cmp *)e->data; + int len = size, offset = 0, ret, i; + + ret = snprintf(buf, len, "sreg=%u op=%s data=", + cmp->sreg, expr_cmp_str[cmp->op]); + SNPRINTF_BUFFER_SIZE(ret, size, len, offset); + + for (i=0; idata.len/sizeof(uint32_t); i++) { + ret = snprintf(buf+offset, len, "%.8x ", cmp->data.val[i]); + SNPRINTF_BUFFER_SIZE(ret, size, len, offset); + } + return offset; +} + +struct expr_ops expr_ops_cmp = { + .name = "cmp", + .alloc_len = sizeof(struct nft_expr_cmp), + .max_attr = NFTA_CMP_MAX, + .set = nft_rule_expr_cmp_set, + .get = nft_rule_expr_cmp_get, + .parse = nft_rule_expr_cmp_parse, + .build = nft_rule_expr_cmp_build, + .snprintf = nft_rule_expr_cmp_snprintf, +}; -- cgit v1.2.3