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Diffstat (limited to '')
| -rw-r--r-- | src/expr/inner.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/src/expr/inner.c b/src/expr/inner.c new file mode 100644 index 0000000..7daae4f --- /dev/null +++ b/src/expr/inner.c @@ -0,0 +1,214 @@ +/* + * (C) 2012-2022 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. + */ + +#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_inner { + uint32_t type; + uint32_t flags; + uint32_t hdrsize; + struct nftnl_expr *expr; +}; + +static void nftnl_expr_inner_free(const struct nftnl_expr *e) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + + if (inner->expr) + nftnl_expr_free(inner->expr); +} + +static int +nftnl_expr_inner_set(struct nftnl_expr *e, uint16_t type, + const void *data, uint32_t data_len) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_INNER_TYPE: + memcpy(&inner->type, data, sizeof(inner->type)); + break; + case NFTNL_EXPR_INNER_FLAGS: + memcpy(&inner->flags, data, sizeof(inner->flags)); + break; + case NFTNL_EXPR_INNER_HDRSIZE: + memcpy(&inner->hdrsize, data, sizeof(inner->hdrsize)); + break; + case NFTNL_EXPR_INNER_EXPR: + if (inner->expr) + nftnl_expr_free(inner->expr); + + inner->expr = (void *)data; + break; + default: + return -1; + } + return 0; +} + +static const void * +nftnl_expr_inner_get(const struct nftnl_expr *e, uint16_t type, + uint32_t *data_len) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + + switch(type) { + case NFTNL_EXPR_INNER_FLAGS: + *data_len = sizeof(inner->flags); + return &inner->flags; + case NFTNL_EXPR_INNER_TYPE: + *data_len = sizeof(inner->type); + return &inner->type; + case NFTNL_EXPR_INNER_HDRSIZE: + *data_len = sizeof(inner->hdrsize); + return &inner->hdrsize; + case NFTNL_EXPR_INNER_EXPR: + return inner->expr; + } + return NULL; +} + +static void +nftnl_expr_inner_build(struct nlmsghdr *nlh, const struct nftnl_expr *e) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + struct nlattr *nest; + + mnl_attr_put_u32(nlh, NFTA_INNER_NUM, htonl(0)); + if (e->flags & (1 << NFTNL_EXPR_INNER_TYPE)) + mnl_attr_put_u32(nlh, NFTA_INNER_TYPE, htonl(inner->type)); + if (e->flags & (1 << NFTNL_EXPR_INNER_FLAGS)) + mnl_attr_put_u32(nlh, NFTA_INNER_FLAGS, htonl(inner->flags)); + if (e->flags & (1 << NFTNL_EXPR_INNER_HDRSIZE)) + mnl_attr_put_u32(nlh, NFTA_INNER_HDRSIZE, htonl(inner->hdrsize)); + if (e->flags & (1 << NFTNL_EXPR_INNER_EXPR)) { + nest = mnl_attr_nest_start(nlh, NFTA_INNER_EXPR); + nftnl_expr_build_payload(nlh, inner->expr); + mnl_attr_nest_end(nlh, nest); + } +} + +static int nftnl_inner_parse_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_INNER_MAX) < 0) + return MNL_CB_OK; + + switch(type) { + case NFTA_INNER_NUM: + case NFTA_INNER_TYPE: + case NFTA_INNER_HDRSIZE: + case NFTA_INNER_FLAGS: + if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) + abi_breakage(); + break; + case NFTA_INNER_EXPR: + if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0) + abi_breakage(); + break; + } + + tb[type] = attr; + + return MNL_CB_OK; +} + +static int +nftnl_expr_inner_parse(struct nftnl_expr *e, struct nlattr *attr) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + struct nlattr *tb[NFTA_INNER_MAX + 1] = {}; + struct nftnl_expr *expr; + int err; + + err = mnl_attr_parse_nested(attr, nftnl_inner_parse_cb, tb); + if (err < 0) + return err; + + if (tb[NFTA_INNER_HDRSIZE]) { + inner->hdrsize = + ntohl(mnl_attr_get_u32(tb[NFTA_INNER_HDRSIZE])); + e->flags |= (1 << NFTNL_EXPR_INNER_HDRSIZE); + } + if (tb[NFTA_INNER_FLAGS]) { + inner->flags = + ntohl(mnl_attr_get_u32(tb[NFTA_INNER_FLAGS])); + e->flags |= (1 << NFTNL_EXPR_INNER_FLAGS); + } + if (tb[NFTA_INNER_TYPE]) { + inner->type = + ntohl(mnl_attr_get_u32(tb[NFTA_INNER_TYPE])); + e->flags |= (1 << NFTNL_EXPR_INNER_TYPE); + } + if (tb[NFTA_INNER_EXPR]) { + expr = nftnl_expr_parse(tb[NFTA_INNER_EXPR]); + if (!expr) + return -1; + + if (inner->expr) + nftnl_expr_free(inner->expr); + + inner->expr = expr; + e->flags |= (1 << NFTNL_EXPR_INNER_EXPR); + } + + return 0; +} + +static int +nftnl_expr_inner_snprintf(char *buf, size_t remain, uint32_t flags, + const struct nftnl_expr *e) +{ + struct nftnl_expr_inner *inner = nftnl_expr_data(e); + uint32_t offset = 0; + int ret; + + ret = snprintf(buf, remain, "type %u hdrsize %u flags %x [", + inner->type, inner->hdrsize, inner->flags); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = snprintf(buf + offset, remain, " %s ", inner->expr->ops->name); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = nftnl_expr_snprintf(buf + offset, remain, inner->expr, + NFTNL_OUTPUT_DEFAULT, 0); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + ret = snprintf(buf + offset, remain, "] "); + SNPRINTF_BUFFER_SIZE(ret, remain, offset); + + return offset; +} + +struct expr_ops expr_ops_inner = { + .name = "inner", + .alloc_len = sizeof(struct nftnl_expr_inner), + .max_attr = NFTA_INNER_MAX, + .free = nftnl_expr_inner_free, + .set = nftnl_expr_inner_set, + .get = nftnl_expr_inner_get, + .parse = nftnl_expr_inner_parse, + .build = nftnl_expr_inner_build, + .output = nftnl_expr_inner_snprintf, +}; |