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authorFernando Fernandez Mancera <ffmancera@riseup.net>2019-06-19 19:53:50 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2019-07-06 00:03:55 +0200
commita6a2d0c9fd97196a98cdf5f1389cd64eae7974b9 (patch)
tree360d117c307301168e8482781cde0f156db34f0d /src
parent78709f7b55aa8934f42aa40548dcdf65e6bfeb2c (diff)
src: add synproxy support
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src')
-rw-r--r--src/Makefile.am1
-rw-r--r--src/expr/synproxy.c170
-rw-r--r--src/expr_ops.c2
3 files changed, 173 insertions, 0 deletions
diff --git a/src/Makefile.am b/src/Makefile.am
index 8f9c022..f16422c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -56,6 +56,7 @@ libnftnl_la_SOURCES = utils.c \
expr/redir.c \
expr/hash.c \
expr/socket.c \
+ expr/synproxy.c \
expr/osf.c \
expr/xfrm.c \
obj/counter.c \
diff --git a/src/expr/synproxy.c b/src/expr/synproxy.c
new file mode 100644
index 0000000..245f4fb
--- /dev/null
+++ b/src/expr/synproxy.c
@@ -0,0 +1,170 @@
+#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_synproxy {
+ uint16_t mss;
+ uint8_t wscale;
+ uint32_t flags;
+};
+
+static int nftnl_expr_synproxy_set(struct nftnl_expr *e, uint16_t type,
+ const void *data, uint32_t data_len)
+{
+ struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
+
+ switch(type) {
+ case NFTNL_EXPR_SYNPROXY_MSS:
+ memcpy(&synproxy->mss, data, sizeof(synproxy->mss));
+ break;
+ case NFTNL_EXPR_SYNPROXY_WSCALE:
+ memcpy(&synproxy->wscale, data, sizeof(synproxy->wscale));
+ break;
+ case NFTNL_EXPR_SYNPROXY_FLAGS:
+ memcpy(&synproxy->flags, data, sizeof(synproxy->flags));
+ break;
+ }
+ return 0;
+}
+
+static const void *
+nftnl_expr_synproxy_get(const struct nftnl_expr *e, uint16_t type,
+ uint32_t *data_len)
+{
+ struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
+
+ switch(type) {
+ case NFTNL_EXPR_SYNPROXY_MSS:
+ *data_len = sizeof(synproxy->mss);
+ return &synproxy->mss;
+ case NFTNL_EXPR_SYNPROXY_WSCALE:
+ *data_len = sizeof(synproxy->wscale);
+ return &synproxy->wscale;
+ case NFTNL_EXPR_SYNPROXY_FLAGS:
+ *data_len = sizeof(synproxy->flags);
+ return &synproxy->flags;
+ }
+ return NULL;
+}
+
+static int nftnl_expr_synproxy_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_SYNPROXY_MAX) < 0)
+ return MNL_CB_OK;
+
+ switch(type) {
+ case NFTNL_EXPR_SYNPROXY_MSS:
+ if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
+ abi_breakage();
+ break;
+
+ case NFTNL_EXPR_SYNPROXY_WSCALE:
+ if (mnl_attr_validate(attr, MNL_TYPE_U8) < 0)
+ abi_breakage();
+ break;
+
+ case NFTNL_EXPR_SYNPROXY_FLAGS:
+ if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
+ abi_breakage();
+ break;
+ }
+
+ tb[type] = attr;
+ return MNL_CB_OK;
+}
+
+static void
+nftnl_expr_synproxy_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
+{
+ struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
+
+ if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_MSS))
+ mnl_attr_put_u16(nlh, NFTNL_EXPR_SYNPROXY_MSS,
+ htons(synproxy->mss));
+ if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_WSCALE))
+ mnl_attr_put_u8(nlh, NFTNL_EXPR_SYNPROXY_WSCALE,
+ synproxy->wscale);
+ if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_FLAGS))
+ mnl_attr_put_u32(nlh, NFTNL_EXPR_SYNPROXY_FLAGS,
+ htonl(synproxy->flags));
+}
+
+static int
+nftnl_expr_synproxy_parse(struct nftnl_expr *e, struct nlattr *attr)
+{
+ struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
+ struct nlattr *tb[NFTA_SYNPROXY_MAX + 1] = {};
+
+ if (mnl_attr_parse_nested(attr, nftnl_expr_synproxy_cb, tb) < 0)
+ return -1;
+
+ if (tb[NFTA_SYNPROXY_MSS]) {
+ synproxy->mss = ntohs(mnl_attr_get_u16(tb[NFTA_SYNPROXY_MSS]));
+ e->flags |= (1 << NFTNL_EXPR_SYNPROXY_MSS);
+ }
+
+ if (tb[NFTA_SYNPROXY_WSCALE]) {
+ synproxy->wscale = mnl_attr_get_u8(tb[NFTA_SYNPROXY_WSCALE]);
+ e->flags |= (1 << NFTNL_EXPR_SYNPROXY_WSCALE);
+ }
+
+ if (tb[NFTA_SYNPROXY_FLAGS]) {
+ synproxy->flags = ntohl(mnl_attr_get_u32(tb[NFTA_SYNPROXY_FLAGS]));
+ e->flags |= (1 << NFTNL_EXPR_SYNPROXY_FLAGS);
+ }
+
+ return 0;
+}
+
+static int nftnl_expr_synproxy_snprintf_default(char *buf, size_t size,
+ const struct nftnl_expr *e)
+{
+ struct nftnl_expr_synproxy *synproxy = nftnl_expr_data(e);
+ int ret, offset = 0, len = size;
+
+ if (e->flags & (1 << NFTNL_EXPR_SYNPROXY_MSS) &&
+ e->flags & (1 << NFTNL_EXPR_SYNPROXY_WSCALE)) {
+ ret = snprintf(buf, len, "mss %u wscale %u ", synproxy->mss,
+ synproxy->wscale);
+ SNPRINTF_BUFFER_SIZE(ret, len, offset);
+ }
+
+ return offset;
+}
+
+static int
+nftnl_expr_synproxy_snprintf(char *buf, size_t len, uint32_t type,
+ uint32_t flags, const struct nftnl_expr *e)
+{
+ switch(type) {
+ case NFTNL_OUTPUT_DEFAULT:
+ return nftnl_expr_synproxy_snprintf_default(buf, len, e);
+ case NFTNL_OUTPUT_XML:
+ case NFTNL_OUTPUT_JSON:
+ default:
+ break;
+ }
+ return -1;
+}
+
+struct expr_ops expr_ops_synproxy = {
+ .name = "synproxy",
+ .alloc_len = sizeof(struct nftnl_expr_synproxy),
+ .max_attr = NFTA_SYNPROXY_MAX,
+ .set = nftnl_expr_synproxy_set,
+ .get = nftnl_expr_synproxy_get,
+ .parse = nftnl_expr_synproxy_parse,
+ .build = nftnl_expr_synproxy_build,
+ .snprintf = nftnl_expr_synproxy_snprintf,
+};
diff --git a/src/expr_ops.c b/src/expr_ops.c
index 051140f..3538dd6 100644
--- a/src/expr_ops.c
+++ b/src/expr_ops.c
@@ -37,6 +37,7 @@ extern struct expr_ops expr_ops_hash;
extern struct expr_ops expr_ops_fib;
extern struct expr_ops expr_ops_flow;
extern struct expr_ops expr_ops_socket;
+extern struct expr_ops expr_ops_synproxy;
extern struct expr_ops expr_ops_tunnel;
extern struct expr_ops expr_ops_osf;
extern struct expr_ops expr_ops_xfrm;
@@ -80,6 +81,7 @@ static struct expr_ops *expr_ops[] = {
&expr_ops_objref,
&expr_ops_flow,
&expr_ops_socket,
+ &expr_ops_synproxy,
&expr_ops_tunnel,
&expr_ops_osf,
&expr_ops_xfrm,