From cb6c9cf5ac8bc43957f719e86222b32713f38e8b Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Tue, 11 Jun 2013 14:20:15 +0200 Subject: expr: add exthdr This patch adds support for the exthdr expression of nftables that is implemented in linux/net/netfilter/nft_exthdr.c Signed-off-by: Pablo Neira Ayuso --- src/expr/exthdr.c | 292 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 292 insertions(+) create mode 100644 src/expr/exthdr.c (limited to 'src/expr/exthdr.c') diff --git a/src/expr/exthdr.c b/src/expr/exthdr.c new file mode 100644 index 0000000..fb3f7ad --- /dev/null +++ b/src/expr/exthdr.c @@ -0,0 +1,292 @@ +/* + * (C) 2012-2013 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 +#include + +#include "expr_ops.h" + +struct nft_expr_exthdr { + enum nft_registers dreg; + uint8_t type; + unsigned int offset; + unsigned int len; +}; + +static int +nft_rule_expr_exthdr_set(struct nft_rule_expr *e, uint16_t type, + const void *data, size_t data_len) +{ + struct nft_expr_exthdr *exthdr = (struct nft_expr_exthdr *)e->data; + + switch(type) { + case NFT_EXPR_EXTHDR_DREG: + exthdr->dreg = *((uint32_t *)data); + break; + case NFT_EXPR_EXTHDR_TYPE: + exthdr->type = *((uint8_t *)data); + break; + case NFT_EXPR_EXTHDR_OFFSET: + exthdr->offset = *((unsigned int *)data); + break; + case NFT_EXPR_EXTHDR_LEN: + exthdr->len = *((unsigned int *)data); + break; + default: + return -1; + } + return 0; +} + +static const void * +nft_rule_expr_exthdr_get(struct nft_rule_expr *e, uint16_t type, size_t *data_len) +{ + struct nft_expr_exthdr *exthdr = (struct nft_expr_exthdr *)e->data; + + switch(type) { + case NFT_EXPR_EXTHDR_DREG: + if (e->flags & (1 << NFT_EXPR_EXTHDR_DREG)) { + *data_len = sizeof(exthdr->dreg); + return &exthdr->dreg; + } else + return NULL; + break; + case NFT_EXPR_EXTHDR_TYPE: + if (e->flags & (1 << NFT_EXPR_EXTHDR_TYPE)) { + *data_len = sizeof(exthdr->type); + return &exthdr->type; + } else + return NULL; + break; + case NFT_EXPR_EXTHDR_OFFSET: + if (e->flags & (1 << NFT_EXPR_EXTHDR_OFFSET)) { + *data_len = sizeof(exthdr->offset); + return &exthdr->offset; + } else + return NULL; + break; + case NFT_EXPR_EXTHDR_LEN: + if (e->flags & (1 << NFT_EXPR_EXTHDR_LEN)) { + *data_len = sizeof(exthdr->len); + return &exthdr->len; + } else + return NULL; + break; + default: + break; + } + return NULL; +} + +static int nft_rule_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) { + perror("mnl_attr_validate"); + return MNL_CB_ERROR; + } + break; + case NFTA_EXTHDR_DREG: + case NFTA_EXTHDR_OFFSET: + case NFTA_EXTHDR_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_exthdr_build(struct nlmsghdr *nlh, struct nft_rule_expr *e) +{ + struct nft_expr_exthdr *exthdr = (struct nft_expr_exthdr *)e->data; + + if (e->flags & (1 << NFT_EXPR_EXTHDR_DREG)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_DREG, htonl(exthdr->dreg)); + if (e->flags & (1 << NFT_EXPR_EXTHDR_TYPE)) + mnl_attr_put_u8(nlh, NFTA_EXTHDR_TYPE, exthdr->type); + if (e->flags & (1 << NFT_EXPR_EXTHDR_OFFSET)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_OFFSET, htonl(exthdr->offset)); + if (e->flags & (1 << NFT_EXPR_EXTHDR_LEN)) + mnl_attr_put_u32(nlh, NFTA_EXTHDR_LEN, htonl(exthdr->len)); +} + +static int +nft_rule_expr_exthdr_parse(struct nft_rule_expr *e, struct nlattr *attr) +{ + struct nft_expr_exthdr *exthdr = (struct nft_expr_exthdr *)e->data; + struct nlattr *tb[NFTA_EXTHDR_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nft_rule_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 << NFT_EXPR_EXTHDR_DREG); + } + if (tb[NFTA_EXTHDR_TYPE]) { + exthdr->type = mnl_attr_get_u8(tb[NFTA_EXTHDR_TYPE]); + e->flags |= (1 << NFT_EXPR_EXTHDR_TYPE); + } + if (tb[NFTA_EXTHDR_OFFSET]) { + exthdr->offset = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_OFFSET])); + e->flags |= (1 << NFT_EXPR_EXTHDR_OFFSET); + } + if (tb[NFTA_EXTHDR_LEN]) { + exthdr->len = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_LEN])); + e->flags |= (1 << NFT_EXPR_EXTHDR_LEN); + } + + return 0; +} + +static int +nft_rule_expr_exthdr_xml_parse(struct nft_rule_expr *e, char *xml) +{ +#ifdef XML_PARSING + struct nft_expr_exthdr *exthdr = (struct nft_expr_exthdr *)e->data; + mxml_node_t *tree = NULL; + mxml_node_t *node = NULL; + uint64_t tmp; + char *endptr; + + tree = mxmlLoadString(NULL, xml, MXML_OPAQUE_CALLBACK); + if (tree == NULL) + return -1; + + if (mxmlElementGetAttr(tree, "type") == NULL) { + mxmlDelete(tree); + return -1; + } + + if (strcmp("exthdr", mxmlElementGetAttr(tree, "type")) != 0) { + mxmlDelete(tree); + return -1; + } + + /* Get and set . Not mandatory */ + node = mxmlFindElement(tree, tree, "dreg", NULL, NULL, + MXML_DESCEND_FIRST); + if (node != NULL) { + tmp = strtoull(node->child->value.opaque, &endptr, 10); + if (tmp > UINT32_MAX || tmp < 0 || *endptr) { + mxmlDelete(tree); + return -1; + } + + exthdr->dreg = tmp; + e->flags |= (1 << NFT_EXPR_EXTHDR_DREG); + } + + /* Get and set . Not mandatory */ + node = mxmlFindElement(tree, tree, "type", NULL, NULL, MXML_DESCEND); + if (node != NULL) { + tmp = strtoull(node->child->value.opaque, &endptr, 10); + if (tmp > UINT8_MAX || tmp < 0 || *endptr) { + mxmlDelete(tree); + return -1; + } + + exthdr->type = tmp; + e->flags |= (1 << NFT_EXPR_EXTHDR_TYPE); + } + + /* Get and set . Not mandatory */ + node = mxmlFindElement(tree, tree, "offset", NULL, NULL, + MXML_DESCEND); + if (node != NULL) { + tmp = strtoull(node->child->value.opaque, &endptr, 10); + if (tmp > UINT_MAX || tmp < 0 || *endptr) { + mxmlDelete(tree); + return -1; + } + + exthdr->offset = tmp; + e->flags |= (1 << NFT_EXPR_EXTHDR_OFFSET); + } + + /* Get and set . Not mandatory */ + node = mxmlFindElement(tree, tree, "len", NULL, NULL, MXML_DESCEND); + if (node != NULL) { + tmp = strtoull(node->child->value.opaque, &endptr, 10); + if (tmp > UINT_MAX || tmp < 0 || *endptr) { + mxmlDelete(tree); + return -1; + } + + exthdr->len = tmp; + e->flags |= (1 << NFT_EXPR_EXTHDR_LEN); + } + mxmlDelete(tree); + return 0; +#else + errno = EOPNOTSUPP; + return -1; +#endif +} + +static int +nft_rule_expr_exthdr_snprintf(char *buf, size_t len, uint32_t type, + uint32_t flags, struct nft_rule_expr *e) +{ + struct nft_expr_exthdr *exthdr = (struct nft_expr_exthdr *)e->data; + + switch(type) { + case NFT_RULE_O_XML: + return snprintf(buf, len, "%u" + "%u%u" + "%u", + exthdr->dreg, exthdr->type, + exthdr->offset, exthdr->len); + + case NFT_RULE_O_DEFAULT: + return snprintf(buf, len, "dreg=%u type=%u offset=%u len=%u ", + exthdr->dreg, exthdr->type, + exthdr->offset, exthdr->len); + default: + break; + } + return -1; +} + +struct expr_ops expr_ops_exthdr = { + .name = "exthdr", + .alloc_len = sizeof(struct nft_expr_exthdr), + .max_attr = NFTA_EXTHDR_MAX, + .set = nft_rule_expr_exthdr_set, + .get = nft_rule_expr_exthdr_get, + .parse = nft_rule_expr_exthdr_parse, + .build = nft_rule_expr_exthdr_build, + .snprintf = nft_rule_expr_exthdr_snprintf, + .xml_parse = nft_rule_expr_exthdr_xml_parse, +}; -- cgit v1.2.3