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-rw-r--r--src/expr/exthdr.c271
1 files changed, 271 insertions, 0 deletions
diff --git a/src/expr/exthdr.c b/src/expr/exthdr.c
new file mode 100644
index 0000000..739c7ff
--- /dev/null
+++ b/src/expr/exthdr.c
@@ -0,0 +1,271 @@
+/*
+ * (C) 2012-2013 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 <string.h>
+#include <stdint.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>
+
+#ifndef IPPROTO_MH
+#define IPPROTO_MH 135
+#endif
+
+struct nftnl_expr_exthdr {
+ enum nft_registers dreg;
+ enum nft_registers sreg;
+ uint32_t offset;
+ uint32_t len;
+ uint8_t type;
+ uint32_t op;
+ uint32_t flags;
+};
+
+static int
+nftnl_expr_exthdr_set(struct nftnl_expr *e, uint16_t type,
+ const void *data, uint32_t data_len)
+{
+ struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
+
+ switch(type) {
+ case NFTNL_EXPR_EXTHDR_DREG:
+ memcpy(&exthdr->dreg, data, sizeof(exthdr->dreg));
+ break;
+ case NFTNL_EXPR_EXTHDR_TYPE:
+ memcpy(&exthdr->type, data, sizeof(exthdr->type));
+ break;
+ case NFTNL_EXPR_EXTHDR_OFFSET:
+ memcpy(&exthdr->offset, data, sizeof(exthdr->offset));
+ break;
+ case NFTNL_EXPR_EXTHDR_LEN:
+ memcpy(&exthdr->len, data, sizeof(exthdr->len));
+ break;
+ case NFTNL_EXPR_EXTHDR_OP:
+ memcpy(&exthdr->op, data, sizeof(exthdr->op));
+ break;
+ case NFTNL_EXPR_EXTHDR_FLAGS:
+ memcpy(&exthdr->flags, data, sizeof(exthdr->flags));
+ break;
+ case NFTNL_EXPR_EXTHDR_SREG:
+ memcpy(&exthdr->sreg, data, sizeof(exthdr->sreg));
+ break;
+ default:
+ return -1;
+ }
+ return 0;
+}
+
+static const void *
+nftnl_expr_exthdr_get(const struct nftnl_expr *e, uint16_t type,
+ uint32_t *data_len)
+{
+ struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
+
+ switch(type) {
+ case NFTNL_EXPR_EXTHDR_DREG:
+ *data_len = sizeof(exthdr->dreg);
+ return &exthdr->dreg;
+ case NFTNL_EXPR_EXTHDR_TYPE:
+ *data_len = sizeof(exthdr->type);
+ return &exthdr->type;
+ case NFTNL_EXPR_EXTHDR_OFFSET:
+ *data_len = sizeof(exthdr->offset);
+ return &exthdr->offset;
+ case NFTNL_EXPR_EXTHDR_LEN:
+ *data_len = sizeof(exthdr->len);
+ return &exthdr->len;
+ case NFTNL_EXPR_EXTHDR_OP:
+ *data_len = sizeof(exthdr->op);
+ return &exthdr->op;
+ case NFTNL_EXPR_EXTHDR_FLAGS:
+ *data_len = sizeof(exthdr->flags);
+ return &exthdr->flags;
+ case NFTNL_EXPR_EXTHDR_SREG:
+ *data_len = sizeof(exthdr->sreg);
+ return &exthdr->sreg;
+ }
+ return NULL;
+}
+
+static int nftnl_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)
+ abi_breakage();
+ break;
+ case NFTA_EXTHDR_DREG:
+ case NFTA_EXTHDR_SREG:
+ case NFTA_EXTHDR_OFFSET:
+ case NFTA_EXTHDR_LEN:
+ case NFTA_EXTHDR_OP:
+ case NFTA_EXTHDR_FLAGS:
+ if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+ abi_breakage();
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static void
+nftnl_expr_exthdr_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
+{
+ struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
+
+ if (e->flags & (1 << NFTNL_EXPR_EXTHDR_DREG))
+ mnl_attr_put_u32(nlh, NFTA_EXTHDR_DREG, htonl(exthdr->dreg));
+ if (e->flags & (1 << NFTNL_EXPR_EXTHDR_SREG))
+ mnl_attr_put_u32(nlh, NFTA_EXTHDR_SREG, htonl(exthdr->sreg));
+ if (e->flags & (1 << NFTNL_EXPR_EXTHDR_TYPE))
+ mnl_attr_put_u8(nlh, NFTA_EXTHDR_TYPE, exthdr->type);
+ if (e->flags & (1 << NFTNL_EXPR_EXTHDR_OFFSET))
+ mnl_attr_put_u32(nlh, NFTA_EXTHDR_OFFSET, htonl(exthdr->offset));
+ if (e->flags & (1 << NFTNL_EXPR_EXTHDR_LEN))
+ mnl_attr_put_u32(nlh, NFTA_EXTHDR_LEN, htonl(exthdr->len));
+ if (e->flags & (1 << NFTNL_EXPR_EXTHDR_OP))
+ mnl_attr_put_u32(nlh, NFTA_EXTHDR_OP, htonl(exthdr->op));
+ if (e->flags & (1 << NFTNL_EXPR_EXTHDR_FLAGS))
+ mnl_attr_put_u32(nlh, NFTA_EXTHDR_FLAGS, htonl(exthdr->flags));
+}
+
+static int
+nftnl_expr_exthdr_parse(struct nftnl_expr *e, struct nlattr *attr)
+{
+ struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
+ struct nlattr *tb[NFTA_EXTHDR_MAX+1] = {};
+
+ if (mnl_attr_parse_nested(attr, nftnl_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 << NFTNL_EXPR_EXTHDR_DREG);
+ }
+ if (tb[NFTA_EXTHDR_SREG]) {
+ exthdr->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_SREG]));
+ e->flags |= (1 << NFTNL_EXPR_EXTHDR_SREG);
+ }
+ if (tb[NFTA_EXTHDR_TYPE]) {
+ exthdr->type = mnl_attr_get_u8(tb[NFTA_EXTHDR_TYPE]);
+ e->flags |= (1 << NFTNL_EXPR_EXTHDR_TYPE);
+ }
+ if (tb[NFTA_EXTHDR_OFFSET]) {
+ exthdr->offset = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_OFFSET]));
+ e->flags |= (1 << NFTNL_EXPR_EXTHDR_OFFSET);
+ }
+ if (tb[NFTA_EXTHDR_LEN]) {
+ exthdr->len = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_LEN]));
+ e->flags |= (1 << NFTNL_EXPR_EXTHDR_LEN);
+ }
+ if (tb[NFTA_EXTHDR_OP]) {
+ exthdr->op = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_OP]));
+ e->flags |= (1 << NFTNL_EXPR_EXTHDR_OP);
+ }
+ if (tb[NFTA_EXTHDR_FLAGS]) {
+ exthdr->flags = ntohl(mnl_attr_get_u32(tb[NFTA_EXTHDR_FLAGS]));
+ e->flags |= (1 << NFTNL_EXPR_EXTHDR_FLAGS);
+ }
+
+ return 0;
+}
+
+static const char *op2str(uint8_t op)
+{
+ switch (op) {
+ case NFT_EXTHDR_OP_TCPOPT:
+ return " tcpopt";
+ case NFT_EXTHDR_OP_IPV6:
+ return " ipv6";
+ case NFT_EXTHDR_OP_IPV4:
+ return " ipv4";
+ default:
+ return "";
+ }
+}
+
+static inline int str2exthdr_op(const char* str)
+{
+ if (!strcmp(str, "tcpopt"))
+ return NFT_EXTHDR_OP_TCPOPT;
+ if (!strcmp(str, "ipv4"))
+ return NFT_EXTHDR_OP_IPV4;
+
+ /* if str == "ipv6" or anything else */
+ return NFT_EXTHDR_OP_IPV6;
+}
+
+static inline int str2exthdr_type(const char *str)
+{
+ if (strcmp(str, "hopopts") == 0)
+ return IPPROTO_HOPOPTS;
+ else if (strcmp(str, "routing") == 0)
+ return IPPROTO_ROUTING;
+ else if (strcmp(str, "fragment") == 0)
+ return IPPROTO_FRAGMENT;
+ else if (strcmp(str, "dstopts") == 0)
+ return IPPROTO_DSTOPTS;
+ else if (strcmp(str, "mh") == 0)
+ return IPPROTO_MH;
+
+ return -1;
+}
+
+static int
+nftnl_expr_exthdr_snprintf(char *buf, size_t len,
+ uint32_t flags, const struct nftnl_expr *e)
+{
+ struct nftnl_expr_exthdr *exthdr = nftnl_expr_data(e);
+
+ if (e->flags & (1 << NFTNL_EXPR_EXTHDR_DREG))
+ return snprintf(buf, len, "load%s %ub @ %u + %u%s => reg %u ",
+ op2str(exthdr->op), exthdr->len, exthdr->type,
+ exthdr->offset,
+ exthdr->flags & NFT_EXTHDR_F_PRESENT ? " present" : "",
+ exthdr->dreg);
+ else if (e->flags & (1 << NFTNL_EXPR_EXTHDR_SREG))
+ return snprintf(buf, len, "write%s reg %u => %ub @ %u + %u ",
+ op2str(exthdr->op), exthdr->sreg, exthdr->len, exthdr->type,
+ exthdr->offset);
+ else if (exthdr->op == NFT_EXTHDR_OP_TCPOPT && exthdr->len == 0)
+ return snprintf(buf, len, "reset tcpopt %u ", exthdr->type);
+ else
+ return snprintf(buf, len, "op %u len %u type %u offset %u ",
+ exthdr->op, exthdr->len, exthdr->type, exthdr->offset);
+
+}
+
+struct expr_ops expr_ops_exthdr = {
+ .name = "exthdr",
+ .alloc_len = sizeof(struct nftnl_expr_exthdr),
+ .max_attr = NFTA_EXTHDR_MAX,
+ .set = nftnl_expr_exthdr_set,
+ .get = nftnl_expr_exthdr_get,
+ .parse = nftnl_expr_exthdr_parse,
+ .build = nftnl_expr_exthdr_build,
+ .output = nftnl_expr_exthdr_snprintf,
+};