diff options
Diffstat (limited to 'src/expr/cmp.c')
| -rw-r--r-- | src/expr/cmp.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/expr/cmp.c b/src/expr/cmp.c new file mode 100644 index 0000000..f9d15bb --- /dev/null +++ b/src/expr/cmp.c @@ -0,0 +1,206 @@ +/* + * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org> + * + * 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 <http://www.sophos.com> + */ + +#include "internal.h" + +#include <stdio.h> +#include <stdint.h> +#include <string.h> +#include <arpa/inet.h> +#include <errno.h> + +#include <libmnl/libmnl.h> +#include <linux/netfilter/nf_tables.h> +#include <libnftnl/expr.h> +#include <libnftnl/rule.h> + +struct nftnl_expr_cmp { + union nftnl_data_reg data; + enum nft_registers sreg; + enum nft_cmp_ops op; +}; + +static int +nftnl_expr_cmp_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_cmp *cmp = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_CMP_SREG: + memcpy(&cmp->sreg, data, sizeof(cmp->sreg)); + break; + case NFTNL_EXPR_CMP_OP: + memcpy(&cmp->op, data, sizeof(cmp->op)); + break; + case NFTNL_EXPR_CMP_DATA: + memcpy(&cmp->data.val, data, data_len); + cmp->data.len = data_len; + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_cmp_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_cmp *cmp = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_CMP_SREG: + *data_len = sizeof(cmp->sreg); + return &cmp->sreg; + case NFTNL_EXPR_CMP_OP: + *data_len = sizeof(cmp->op); + return &cmp->op; + case NFTNL_EXPR_CMP_DATA: + *data_len = cmp->data.len; + return &cmp->data.val; + } + return NULL; +} + +static int nftnl_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) + abi_breakage(); + break; + case NFTA_CMP_DATA: + if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_cmp_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_cmp *cmp = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_CMP_SREG)) + mnl_attr_put_u32(nlh, NFTA_CMP_SREG, htonl(cmp->sreg)); + if (e->flags & (1 << NFTNL_EXPR_CMP_OP)) + mnl_attr_put_u32(nlh, NFTA_CMP_OP, htonl(cmp->op)); + if (e->flags & (1 << NFTNL_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 +nftnl_expr_cmp_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_cmp *cmp = nftnl_expr_data(e); + struct nlattr *tb[NFTA_CMP_MAX+1] = {}; + int ret = 0; + + if (mnl_attr_parse_nested(attr, nftnl_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 = nftnl_parse_data(&cmp->data, tb[NFTA_CMP_DATA], NULL); + e->flags |= (1 << NFTA_CMP_DATA); + } + + return ret; +} + +static const 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 const char *cmp2str(uint32_t op) +{ + if (op > NFT_CMP_GTE) + return "unknown"; + + return expr_cmp_str[op]; +} + +static inline int nftnl_str2cmp(const char *op) +{ + if (strcmp(op, "eq") == 0) + return NFT_CMP_EQ; + else if (strcmp(op, "neq") == 0) + return NFT_CMP_NEQ; + else if (strcmp(op, "lt") == 0) + return NFT_CMP_LT; + else if (strcmp(op, "lte") == 0) + return NFT_CMP_LTE; + else if (strcmp(op, "gt") == 0) + return NFT_CMP_GT; + else if (strcmp(op, "gte") == 0) + return NFT_CMP_GTE; + else { + errno = EINVAL; + return -1; + } +} + +static int +nftnl_expr_cmp_snprintf(char *buf, size_t remain, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_cmp *cmp = nftnl_expr_data(e); + int offset = 0, ret; + + ret = snprintf(buf, remain, "%s reg %u ", + cmp2str(cmp->op), cmp->sreg); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = nftnl_data_reg_snprintf(buf + offset, remain, &cmp->data, + 0, DATA_VALUE); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + return offset; +} + +struct expr_ops expr_ops_cmp = { + .name = "cmp", + .alloc_len = sizeof(struct nftnl_expr_cmp), + .max_attr = NFTA_CMP_MAX, + .set = nftnl_expr_cmp_set, + .get = nftnl_expr_cmp_get, + .parse = nftnl_expr_cmp_parse, + .build = nftnl_expr_cmp_build, + .output = nftnl_expr_cmp_snprintf, +}; |