diff options
Diffstat (limited to '')
| -rw-r--r-- | src/expr/numgen.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/src/expr/numgen.c b/src/expr/numgen.c new file mode 100644 index 0000000..d4020a6 --- /dev/null +++ b/src/expr/numgen.c @@ -0,0 +1,184 @@ +/* + * (C) 2016 by Laura Garcia <nevola@gmail.com> + * + * 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. + * + */ + +#include <stdio.h> +#include <stdint.h> +#include <string.h> +#include <arpa/inet.h> +#include <errno.h> +#include <linux/netfilter/nf_tables.h> + +#include "internal.h" +#include <libmnl/libmnl.h> +#include <libnftnl/expr.h> +#include <libnftnl/rule.h> + +struct nftnl_expr_ng { + enum nft_registers dreg; + unsigned int modulus; + enum nft_ng_types type; + unsigned int offset; +}; + +static int +nftnl_expr_ng_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_ng *ng = nftnl_expr_data(e); + + switch (type) { + case NFTNL_EXPR_NG_DREG: + memcpy(&ng->dreg, data, sizeof(ng->dreg)); + break; + case NFTNL_EXPR_NG_MODULUS: + memcpy(&ng->modulus, data, sizeof(ng->modulus)); + break; + case NFTNL_EXPR_NG_TYPE: + memcpy(&ng->type, data, sizeof(ng->type)); + break; + case NFTNL_EXPR_NG_OFFSET: + memcpy(&ng->offset, data, sizeof(ng->offset)); + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_ng_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_ng *ng = nftnl_expr_data(e); + + switch (type) { + case NFTNL_EXPR_NG_DREG: + *data_len = sizeof(ng->dreg); + return &ng->dreg; + case NFTNL_EXPR_NG_MODULUS: + *data_len = sizeof(ng->modulus); + return &ng->modulus; + case NFTNL_EXPR_NG_TYPE: + *data_len = sizeof(ng->type); + return &ng->type; + case NFTNL_EXPR_NG_OFFSET: + *data_len = sizeof(ng->offset); + return &ng->offset; + } + return NULL; +} + +static int nftnl_expr_ng_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_NG_MAX) < 0) + return MNL_CB_OK; + + switch (type) { + case NFTA_NG_DREG: + case NFTA_NG_MODULUS: + case NFTA_NG_TYPE: + case NFTA_NG_OFFSET: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + return MNL_CB_OK; +} + +static void +nftnl_expr_ng_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_ng *ng = nftnl_expr_data(e); + + if (e->flags & (1 << NFTNL_EXPR_NG_DREG)) + mnl_attr_put_u32(nlh, NFTA_NG_DREG, htonl(ng->dreg)); + if (e->flags & (1 << NFTNL_EXPR_NG_MODULUS)) + mnl_attr_put_u32(nlh, NFTA_NG_MODULUS, htonl(ng->modulus)); + if (e->flags & (1 << NFTNL_EXPR_NG_TYPE)) + mnl_attr_put_u32(nlh, NFTA_NG_TYPE, htonl(ng->type)); + if (e->flags & (1 << NFTNL_EXPR_NG_OFFSET)) + mnl_attr_put_u32(nlh, NFTA_NG_OFFSET, htonl(ng->offset)); +} + +static int +nftnl_expr_ng_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_ng *ng = nftnl_expr_data(e); + struct nlattr *tb[NFTA_NG_MAX+1] = {}; + int ret = 0; + + if (mnl_attr_parse_nested(attr, nftnl_expr_ng_cb, tb) < 0) + return -1; + + if (tb[NFTA_NG_DREG]) { + ng->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_NG_DREG])); + e->flags |= (1 << NFTNL_EXPR_NG_DREG); + } + if (tb[NFTA_NG_MODULUS]) { + ng->modulus = ntohl(mnl_attr_get_u32(tb[NFTA_NG_MODULUS])); + e->flags |= (1 << NFTNL_EXPR_NG_MODULUS); + } + if (tb[NFTA_NG_TYPE]) { + ng->type = ntohl(mnl_attr_get_u32(tb[NFTA_NG_TYPE])); + e->flags |= (1 << NFTNL_EXPR_NG_TYPE); + } + if (tb[NFTA_NG_OFFSET]) { + ng->offset = ntohl(mnl_attr_get_u32(tb[NFTA_NG_OFFSET])); + e->flags |= (1 << NFTNL_EXPR_NG_OFFSET); + } + + return ret; +} + +static int +nftnl_expr_ng_snprintf(char *buf, size_t remain, + uint32_t flags, const struct nftnl_expr *e) +{ + struct nftnl_expr_ng *ng = nftnl_expr_data(e); + int offset = 0, ret; + + switch (ng->type) { + case NFT_NG_INCREMENTAL: + ret = snprintf(buf, remain, "reg %u = inc mod %u ", + ng->dreg, ng->modulus); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + break; + case NFT_NG_RANDOM: + ret = snprintf(buf, remain, "reg %u = random mod %u ", + ng->dreg, ng->modulus); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + break; + default: + return 0; + } + + if (ng->offset) { + ret = snprintf(buf + offset, remain, "offset %u ", ng->offset); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + } + + return offset; +} + +struct expr_ops expr_ops_ng = { + .name = "numgen", + .alloc_len = sizeof(struct nftnl_expr_ng), + .max_attr = NFTA_NG_MAX, + .set = nftnl_expr_ng_set, + .get = nftnl_expr_ng_get, + .parse = nftnl_expr_ng_parse, + .build = nftnl_expr_ng_build, + .output = nftnl_expr_ng_snprintf, +}; |