diff options
Diffstat (limited to 'src/expr/payload.c')
| -rw-r--r-- | src/expr/payload.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/src/expr/payload.c b/src/expr/payload.c new file mode 100644 index 0000000..c633e33 --- /dev/null +++ b/src/expr/payload.c @@ -0,0 +1,250 @@ +/* + * (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 <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> + +struct nftnl_expr_payload { + enum nft_registers sreg; + enum nft_registers dreg; + enum nft_payload_bases base; + uint32_t offset; + uint32_t len; + uint32_t csum_type; + uint32_t csum_offset; + uint32_t csum_flags; +}; + +static int +nftnl_expr_payload_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_payload *payload = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_PAYLOAD_SREG: + memcpy(&payload->sreg, data, sizeof(payload->sreg)); + break; + case NFTNL_EXPR_PAYLOAD_DREG: + memcpy(&payload->dreg, data, sizeof(payload->dreg)); + break; + case NFTNL_EXPR_PAYLOAD_BASE: + memcpy(&payload->base, data, sizeof(payload->base)); + break; + case NFTNL_EXPR_PAYLOAD_OFFSET: + memcpy(&payload->offset, data, sizeof(payload->offset)); + break; + case NFTNL_EXPR_PAYLOAD_LEN: + memcpy(&payload->len, data, sizeof(payload->len)); + break; + case NFTNL_EXPR_PAYLOAD_CSUM_TYPE: + memcpy(&payload->csum_type, data, sizeof(payload->csum_type)); + break; + case NFTNL_EXPR_PAYLOAD_CSUM_OFFSET: + memcpy(&payload->csum_offset, data, sizeof(payload->csum_offset)); + break; + case NFTNL_EXPR_PAYLOAD_FLAGS: + memcpy(&payload->csum_flags, data, sizeof(payload->csum_flags)); + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_payload_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_payload *payload = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_PAYLOAD_SREG: + *data_len = sizeof(payload->sreg); + return &payload->sreg; + case NFTNL_EXPR_PAYLOAD_DREG: + *data_len = sizeof(payload->dreg); + return &payload->dreg; + case NFTNL_EXPR_PAYLOAD_BASE: + *data_len = sizeof(payload->base); + return &payload->base; + case NFTNL_EXPR_PAYLOAD_OFFSET: + *data_len = sizeof(payload->offset); + return &payload->offset; + case NFTNL_EXPR_PAYLOAD_LEN: + *data_len = sizeof(payload->len); + return &payload->len; + case NFTNL_EXPR_PAYLOAD_CSUM_TYPE: + *data_len = sizeof(payload->csum_type); + return &payload->csum_type; + case NFTNL_EXPR_PAYLOAD_CSUM_OFFSET: + *data_len = sizeof(payload->csum_offset); + return &payload->csum_offset; + case NFTNL_EXPR_PAYLOAD_FLAGS: + *data_len = sizeof(payload->csum_flags); + return &payload->csum_flags; + } + return NULL; +} + +static int nftnl_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_SREG: + case NFTA_PAYLOAD_DREG: + case NFTA_PAYLOAD_BASE: + case NFTA_PAYLOAD_OFFSET: + case NFTA_PAYLOAD_LEN: + case NFTA_PAYLOAD_CSUM_TYPE: + case NFTA_PAYLOAD_CSUM_OFFSET: + case NFTA_PAYLOAD_CSUM_FLAGS: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_payload_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_payload *payload = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_PAYLOAD_SREG)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_SREG, htonl(payload->sreg)); + if (e->flags & (1 << NFTNL_EXPR_PAYLOAD_DREG)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_DREG, htonl(payload->dreg)); + if (e->flags & (1 << NFTNL_EXPR_PAYLOAD_BASE)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_BASE, htonl(payload->base)); + if (e->flags & (1 << NFTNL_EXPR_PAYLOAD_OFFSET)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_OFFSET, htonl(payload->offset)); + if (e->flags & (1 << NFTNL_EXPR_PAYLOAD_LEN)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_LEN, htonl(payload->len)); + if (e->flags & (1 << NFTNL_EXPR_PAYLOAD_CSUM_TYPE)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_CSUM_TYPE, + htonl(payload->csum_type)); + if (e->flags & (1 << NFTNL_EXPR_PAYLOAD_CSUM_OFFSET)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_CSUM_OFFSET, + htonl(payload->csum_offset)); + if (e->flags & (1 << NFTNL_EXPR_PAYLOAD_FLAGS)) + mnl_attr_put_u32(nlh, NFTA_PAYLOAD_CSUM_FLAGS, + htonl(payload->csum_flags)); +} + +static int +nftnl_expr_payload_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_payload *payload = nftnl_expr_data(e); + struct nlattr *tb[NFTA_PAYLOAD_MAX+1] = {}; + + if (mnl_attr_parse_nested(attr, nftnl_expr_payload_cb, tb) < 0) + return -1; + + if (tb[NFTA_PAYLOAD_SREG]) { + payload->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_SREG])); + e->flags |= (1 << NFTNL_EXPR_PAYLOAD_SREG); + } + if (tb[NFTA_PAYLOAD_DREG]) { + payload->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_DREG])); + e->flags |= (1 << NFTNL_EXPR_PAYLOAD_DREG); + } + if (tb[NFTA_PAYLOAD_BASE]) { + payload->base = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_BASE])); + e->flags |= (1 << NFTNL_EXPR_PAYLOAD_BASE); + } + if (tb[NFTA_PAYLOAD_OFFSET]) { + payload->offset = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_OFFSET])); + e->flags |= (1 << NFTNL_EXPR_PAYLOAD_OFFSET); + } + if (tb[NFTA_PAYLOAD_LEN]) { + payload->len = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_LEN])); + e->flags |= (1 << NFTNL_EXPR_PAYLOAD_LEN); + } + if (tb[NFTA_PAYLOAD_CSUM_TYPE]) { + payload->csum_type = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_CSUM_TYPE])); + e->flags |= (1 << NFTNL_EXPR_PAYLOAD_CSUM_TYPE); + } + if (tb[NFTA_PAYLOAD_CSUM_OFFSET]) { + payload->csum_offset = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_CSUM_OFFSET])); + e->flags |= (1 << NFTNL_EXPR_PAYLOAD_CSUM_OFFSET); + } + if (tb[NFTA_PAYLOAD_CSUM_FLAGS]) { + payload->csum_flags = ntohl(mnl_attr_get_u32(tb[NFTA_PAYLOAD_CSUM_FLAGS])); + e->flags |= (1 << NFTNL_EXPR_PAYLOAD_FLAGS); + } + return 0; +} + +static const char *base2str_array[NFT_PAYLOAD_TUN_HEADER + 1] = { + [NFT_PAYLOAD_LL_HEADER] = "link", + [NFT_PAYLOAD_NETWORK_HEADER] = "network", + [NFT_PAYLOAD_TRANSPORT_HEADER] = "transport", + [NFT_PAYLOAD_INNER_HEADER] = "inner", + [NFT_PAYLOAD_TUN_HEADER] = "tunnel", +}; + +static const char *base2str(enum nft_payload_bases base) +{ + if (base > NFT_PAYLOAD_INNER_HEADER) + return "unknown"; + + return base2str_array[base]; +} + +static int +nftnl_expr_payload_snprintf(char *buf, size_t len, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_payload *payload = nftnl_expr_data(e); + + if (payload->sreg) + return snprintf(buf, len, "write reg %u => %ub @ %s header + %u csum_type %u csum_off %u csum_flags 0x%x ", + payload->sreg, + payload->len, base2str(payload->base), + payload->offset, payload->csum_type, + payload->csum_offset, + payload->csum_flags); + else + return snprintf(buf, len, "load %ub @ %s header + %u => reg %u ", + payload->len, base2str(payload->base), + payload->offset, payload->dreg); +} + +struct expr_ops expr_ops_payload = { + .name = "payload", + .alloc_len = sizeof(struct nftnl_expr_payload), + .max_attr = NFTA_PAYLOAD_MAX, + .set = nftnl_expr_payload_set, + .get = nftnl_expr_payload_get, + .parse = nftnl_expr_payload_parse, + .build = nftnl_expr_payload_build, + .output = nftnl_expr_payload_snprintf, +}; |