diff options
Diffstat (limited to 'src/expr/bitwise.c')
| -rw-r--r-- | src/expr/bitwise.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/src/expr/bitwise.c b/src/expr/bitwise.c new file mode 100644 index 0000000..2d27233 --- /dev/null +++ b/src/expr/bitwise.c @@ -0,0 +1,286 @@ +/* + * (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> /* for memcpy */ +#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_bitwise { + enum nft_registers sreg; + enum nft_registers dreg; + enum nft_bitwise_ops op; + unsigned int len; + union nftnl_data_reg mask; + union nftnl_data_reg xor; + union nftnl_data_reg data; +}; + +static int +nftnl_expr_bitwise_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_BITWISE_SREG: + memcpy(&bitwise->sreg, data, sizeof(bitwise->sreg)); + break; + case NFTNL_EXPR_BITWISE_DREG: + memcpy(&bitwise->dreg, data, sizeof(bitwise->dreg)); + break; + case NFTNL_EXPR_BITWISE_OP: + memcpy(&bitwise->op, data, sizeof(bitwise->op)); + break; + case NFTNL_EXPR_BITWISE_LEN: + memcpy(&bitwise->len, data, sizeof(bitwise->len)); + break; + case NFTNL_EXPR_BITWISE_MASK: + memcpy(&bitwise->mask.val, data, data_len); + bitwise->mask.len = data_len; + break; + case NFTNL_EXPR_BITWISE_XOR: + memcpy(&bitwise->xor.val, data, data_len); + bitwise->xor.len = data_len; + break; + case NFTNL_EXPR_BITWISE_DATA: + memcpy(&bitwise->data.val, data, data_len); + bitwise->data.len = data_len; + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_bitwise_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_BITWISE_SREG: + *data_len = sizeof(bitwise->sreg); + return &bitwise->sreg; + case NFTNL_EXPR_BITWISE_DREG: + *data_len = sizeof(bitwise->dreg); + return &bitwise->dreg; + case NFTNL_EXPR_BITWISE_OP: + *data_len = sizeof(bitwise->op); + return &bitwise->op; + case NFTNL_EXPR_BITWISE_LEN: + *data_len = sizeof(bitwise->len); + return &bitwise->len; + case NFTNL_EXPR_BITWISE_MASK: + *data_len = bitwise->mask.len; + return &bitwise->mask.val; + case NFTNL_EXPR_BITWISE_XOR: + *data_len = bitwise->xor.len; + return &bitwise->xor.val; + case NFTNL_EXPR_BITWISE_DATA: + *data_len = bitwise->data.len; + return &bitwise->data.val; + } + return NULL; +} + +static int nftnl_expr_bitwise_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_BITWISE_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_BITWISE_SREG: + case NFTA_BITWISE_DREG: + case NFTA_BITWISE_OP: + case NFTA_BITWISE_LEN: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + case NFTA_BITWISE_MASK: + case NFTA_BITWISE_XOR: + case NFTA_BITWISE_DATA: + if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_bitwise_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_BITWISE_SREG)) + mnl_attr_put_u32(nlh, NFTA_BITWISE_SREG, htonl(bitwise->sreg)); + if (e->flags & (1 << NFTNL_EXPR_BITWISE_DREG)) + mnl_attr_put_u32(nlh, NFTA_BITWISE_DREG, htonl(bitwise->dreg)); + if (e->flags & (1 << NFTNL_EXPR_BITWISE_OP)) + mnl_attr_put_u32(nlh, NFTA_BITWISE_OP, htonl(bitwise->op)); + if (e->flags & (1 << NFTNL_EXPR_BITWISE_LEN)) + mnl_attr_put_u32(nlh, NFTA_BITWISE_LEN, htonl(bitwise->len)); + if (e->flags & (1 << NFTNL_EXPR_BITWISE_MASK)) { + struct nlattr *nest; + + nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_MASK); + mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->mask.len, + bitwise->mask.val); + mnl_attr_nest_end(nlh, nest); + } + if (e->flags & (1 << NFTNL_EXPR_BITWISE_XOR)) { + struct nlattr *nest; + + nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_XOR); + mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->xor.len, + bitwise->xor.val); + mnl_attr_nest_end(nlh, nest); + } + if (e->flags & (1 << NFTNL_EXPR_BITWISE_DATA)) { + struct nlattr *nest; + + nest = mnl_attr_nest_start(nlh, NFTA_BITWISE_DATA); + mnl_attr_put(nlh, NFTA_DATA_VALUE, bitwise->data.len, + bitwise->data.val); + mnl_attr_nest_end(nlh, nest); + } +} + +static int +nftnl_expr_bitwise_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e); + struct nlattr *tb[NFTA_BITWISE_MAX+1] = {}; + int ret = 0; + + if (mnl_attr_parse_nested(attr, nftnl_expr_bitwise_cb, tb) < 0) + return -1; + + if (tb[NFTA_BITWISE_SREG]) { + bitwise->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_SREG])); + e->flags |= (1 << NFTNL_EXPR_BITWISE_SREG); + } + if (tb[NFTA_BITWISE_DREG]) { + bitwise->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_DREG])); + e->flags |= (1 << NFTNL_EXPR_BITWISE_DREG); + } + if (tb[NFTA_BITWISE_OP]) { + bitwise->op = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_OP])); + e->flags |= (1 << NFTNL_EXPR_BITWISE_OP); + } + if (tb[NFTA_BITWISE_LEN]) { + bitwise->len = ntohl(mnl_attr_get_u32(tb[NFTA_BITWISE_LEN])); + e->flags |= (1 << NFTNL_EXPR_BITWISE_LEN); + } + if (tb[NFTA_BITWISE_MASK]) { + ret = nftnl_parse_data(&bitwise->mask, tb[NFTA_BITWISE_MASK], NULL); + e->flags |= (1 << NFTA_BITWISE_MASK); + } + if (tb[NFTA_BITWISE_XOR]) { + ret = nftnl_parse_data(&bitwise->xor, tb[NFTA_BITWISE_XOR], NULL); + e->flags |= (1 << NFTA_BITWISE_XOR); + } + if (tb[NFTA_BITWISE_DATA]) { + ret = nftnl_parse_data(&bitwise->data, tb[NFTA_BITWISE_DATA], NULL); + e->flags |= (1 << NFTNL_EXPR_BITWISE_DATA); + } + + return ret; +} + +static int +nftnl_expr_bitwise_snprintf_bool(char *buf, size_t remain, + const struct nftnl_expr_bitwise *bitwise) +{ + int offset = 0, ret; + + ret = snprintf(buf, remain, "reg %u = ( reg %u & ", + bitwise->dreg, bitwise->sreg); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->mask, + 0, DATA_VALUE); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = snprintf(buf + offset, remain, ") ^ "); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->xor, + 0, DATA_VALUE); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + return offset; +} + +static int +nftnl_expr_bitwise_snprintf_shift(char *buf, size_t remain, const char *op, + const struct nftnl_expr_bitwise *bitwise) +{ int offset = 0, ret; + + ret = snprintf(buf, remain, "reg %u = ( reg %u %s ", + bitwise->dreg, bitwise->sreg, op); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = nftnl_data_reg_snprintf(buf + offset, remain, &bitwise->data, + 0, DATA_VALUE); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = snprintf(buf + offset, remain, ") "); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + return offset; +} + +static int +nftnl_expr_bitwise_snprintf(char *buf, size_t size, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_bitwise *bitwise = nftnl_expr_data(e); + int err = -1; + + switch (bitwise->op) { + case NFT_BITWISE_BOOL: + err = nftnl_expr_bitwise_snprintf_bool(buf, size, bitwise); + break; + case NFT_BITWISE_LSHIFT: + err = nftnl_expr_bitwise_snprintf_shift(buf, size, "<<", bitwise); + break; + case NFT_BITWISE_RSHIFT: + err = nftnl_expr_bitwise_snprintf_shift(buf, size, ">>", bitwise); + break; + } + + return err; +} + +struct expr_ops expr_ops_bitwise = { + .name = "bitwise", + .alloc_len = sizeof(struct nftnl_expr_bitwise), + .max_attr = NFTA_BITWISE_MAX, + .set = nftnl_expr_bitwise_set, + .get = nftnl_expr_bitwise_get, + .parse = nftnl_expr_bitwise_parse, + .build = nftnl_expr_bitwise_build, + .output = nftnl_expr_bitwise_snprintf, +}; |