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Diffstat (limited to '')
| -rw-r--r-- | src/expr/exthdr.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/src/expr/exthdr.c b/src/expr/exthdr.c new file mode 100644 index 0000000..739c7ff --- /dev/null +++ b/src/expr/exthdr.c @@ -0,0 +1,271 @@ +/* + * (C) 2012-2013 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 <string.h> +#include <stdint.h> +#include <limits.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> + +#ifndef IPPROTO_MH +#define IPPROTO_MH 135 +#endif + +struct nftnl_expr_exthdr { + enum nft_registers dreg; + enum nft_registers sreg; + uint32_t offset; + uint32_t len; + uint8_t type; + uint32_t op; + uint32_t flags; +}; + +static int +nftnl_expr_exthdr_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_EXTHDR_DREG: + memcpy(&exthdr->dreg, data, sizeof(exthdr->dreg)); + break; + case NFTNL_EXPR_EXTHDR_TYPE: + memcpy(&exthdr->type, data, sizeof(exthdr->type)); + break; + case NFTNL_EXPR_EXTHDR_OFFSET: + memcpy(&exthdr->offset, data, sizeof(exthdr->offset)); + break; + case NFTNL_EXPR_EXTHDR_LEN: + memcpy(&exthdr->len, data, sizeof(exthdr->len)); + break; + case NFTNL_EXPR_EXTHDR_OP: + memcpy(&exthdr->op, data, sizeof(exthdr->op)); + break; + case NFTNL_EXPR_EXTHDR_FLAGS: + memcpy(&exthdr->flags, data, sizeof(exthdr->flags)); + break; + case NFTNL_EXPR_EXTHDR_SREG: + memcpy(&exthdr->sreg, data, sizeof(exthdr->sreg)); + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_exthdr_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_EXTHDR_DREG: + *data_len = sizeof(exthdr->dreg); + return &exthdr->dreg; + case NFTNL_EXPR_EXTHDR_TYPE: + *data_len = sizeof(exthdr->type); + return &exthdr->type; + case NFTNL_EXPR_EXTHDR_OFFSET: + *data_len = sizeof(exthdr->offset); + return &exthdr->offset; + case NFTNL_EXPR_EXTHDR_LEN: + *data_len = sizeof(exthdr->len); + return &exthdr->len; + case NFTNL_EXPR_EXTHDR_OP: + *data_len = sizeof(exthdr->op); + return &exthdr->op; + case NFTNL_EXPR_EXTHDR_FLAGS: + *data_len = sizeof(exthdr->flags); + return &exthdr->flags; + case NFTNL_EXPR_EXTHDR_SREG: + *data_len = sizeof(exthdr->sreg); + return &exthdr->sreg; + } + return NULL; +} + +static int nftnl_expr_exthdr_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_EXTHDR_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_EXTHDR_TYPE: + if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0) + abi_breakage(); + break; + case NFTA_EXTHDR_DREG: + case NFTA_EXTHDR_SREG: + case NFTA_EXTHDR_OFFSET: + case NFTA_EXTHDR_LEN: + case NFTA_EXTHDR_OP: + case NFTA_EXTHDR_FLAGS: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_exthdr_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_EXTHDR_DREG)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_DREG, htonl(exthdr->dreg)); + if (e->flags & (1 << NFTNL_EXPR_EXTHDR_SREG)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_SREG, htonl(exthdr->sreg)); + if (e->flags & (1 << NFTNL_EXPR_EXTHDR_TYPE)) + mnl_attr_put_u8(nlh, NFTA_EXTHDR_TYPE, exthdr->type); + if (e->flags & (1 << NFTNL_EXPR_EXTHDR_OFFSET)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_OFFSET, htonl(exthdr->offset)); + if (e->flags & (1 << NFTNL_EXPR_EXTHDR_LEN)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_LEN, htonl(exthdr->len)); + if (e->flags & (1 << NFTNL_EXPR_EXTHDR_OP)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_OP, htonl(exthdr->op)); + if (e->flags & (1 << NFTNL_EXPR_EXTHDR_FLAGS)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_FLAGS, htonl(exthdr->flags)); +} + +static int +nftnl_expr_exthdr_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e); + struct nlattr *tb[NFTA_EXTHDR_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nftnl_expr_exthdr_cb, tb) < 0) + return -1; + + if (tb[NFTA_EXTHDR_DREG]) { + exthdr->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_DREG])); + e->flags |= (1 << NFTNL_EXPR_EXTHDR_DREG); + } + if (tb[NFTA_EXTHDR_SREG]) { + exthdr->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_SREG])); + e->flags |= (1 << NFTNL_EXPR_EXTHDR_SREG); + } + if (tb[NFTA_EXTHDR_TYPE]) { + exthdr->type = mnl_attr_get_u8(tb[NFTA_EXTHDR_TYPE]); + e->flags |= (1 << NFTNL_EXPR_EXTHDR_TYPE); + } + if (tb[NFTA_EXTHDR_OFFSET]) { + exthdr->offset = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_OFFSET])); + e->flags |= (1 << NFTNL_EXPR_EXTHDR_OFFSET); + } + if (tb[NFTA_EXTHDR_LEN]) { + exthdr->len = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_LEN])); + e->flags |= (1 << NFTNL_EXPR_EXTHDR_LEN); + } + if (tb[NFTA_EXTHDR_OP]) { + exthdr->op = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_OP])); + e->flags |= (1 << NFTNL_EXPR_EXTHDR_OP); + } + if (tb[NFTA_EXTHDR_FLAGS]) { + exthdr->flags = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_FLAGS])); + e->flags |= (1 << NFTNL_EXPR_EXTHDR_FLAGS); + } + + return 0; +} + +static const char *op2str(uint8_t op) +{ + switch (op) { + case NFT_EXTHDR_OP_TCPOPT: + return " tcpopt"; + case NFT_EXTHDR_OP_IPV6: + return " ipv6"; + case NFT_EXTHDR_OP_IPV4: + return " ipv4"; + default: + return ""; + } +} + +static inline int str2exthdr_op(const char* str) +{ + if (!strcmp(str, "tcpopt")) + return NFT_EXTHDR_OP_TCPOPT; + if (!strcmp(str, "ipv4")) + return NFT_EXTHDR_OP_IPV4; + + /* if str == "ipv6" or anything else */ + return NFT_EXTHDR_OP_IPV6; +} + +static inline int str2exthdr_type(const char *str) +{ + if (strcmp(str, "hopopts") == 0) + return IPPROTO_HOPOPTS; + else if (strcmp(str, "routing") == 0) + return IPPROTO_ROUTING; + else if (strcmp(str, "fragment") == 0) + return IPPROTO_FRAGMENT; + else if (strcmp(str, "dstopts") == 0) + return IPPROTO_DSTOPTS; + else if (strcmp(str, "mh") == 0) + return IPPROTO_MH; + + return -1; +} + +static int +nftnl_expr_exthdr_snprintf(char *buf, size_t len, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_EXTHDR_DREG)) + return snprintf(buf, len, "load%s %ub @ %u + %u%s => reg %u ", + op2str(exthdr->op), exthdr->len, exthdr->type, + exthdr->offset, + exthdr->flags & NFT_EXTHDR_F_PRESENT ? " present" : "", + exthdr->dreg); + else if (e->flags & (1 << NFTNL_EXPR_EXTHDR_SREG)) + return snprintf(buf, len, "write%s reg %u => %ub @ %u + %u ", + op2str(exthdr->op), exthdr->sreg, exthdr->len, exthdr->type, + exthdr->offset); + else if (exthdr->op == NFT_EXTHDR_OP_TCPOPT && exthdr->len == 0) + return snprintf(buf, len, "reset tcpopt %u ", exthdr->type); + else + return snprintf(buf, len, "op %u len %u type %u offset %u ", + exthdr->op, exthdr->len, exthdr->type, exthdr->offset); + +} + +struct expr_ops expr_ops_exthdr = { + .name = "exthdr", + .alloc_len = sizeof(struct nftnl_expr_exthdr), + .max_attr = NFTA_EXTHDR_MAX, + .set = nftnl_expr_exthdr_set, + .get = nftnl_expr_exthdr_get, + .parse = nftnl_expr_exthdr_parse, + .build = nftnl_expr_exthdr_build, + .output = nftnl_expr_exthdr_snprintf, +}; |