From 2be1d52644cf77bb2634fb504a265da480c5e901 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?M=C3=A1t=C3=A9=20Eckl?= Date: Fri, 20 Jul 2018 09:40:09 +0200 Subject: src: Add tproxy support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch adds support for transparent proxy functionality which is supported in ip, ip6 and inet tables. The syntax is the following: tproxy [{|ip|ip6}] to {|:|:} It looks for a socket listening on the specified address or port and assigns it to the matching packet. In an inet table, a packet matches for both families until address is specified. Network protocol family has to be specified **only** in inet tables if address is specified. As transparent proxy support is implemented for sockets with layer 4 information, a transport protocol header criterion has to be set in the same rule. eg. 'meta l4proto tcp' or 'udp dport 4444' Example ruleset: table ip x { chain y { type filter hook prerouting priority -150; policy accept; tcp dport ntp tproxy to 1.1.1.1 udp dport ssh tproxy to :2222 } } table ip6 x { chain y { type filter hook prerouting priority -150; policy accept; tcp dport ntp tproxy to [dead::beef] udp dport ssh tproxy to :2222 } } table inet x { chain y { type filter hook prerouting priority -150; policy accept; tcp dport 321 tproxy to :ssh tcp dport 99 tproxy ip to 1.1.1.1:999 udp dport 155 tproxy ip6 to [dead::beef]:smux } } Signed-off-by: Máté Eckl Signed-off-by: Pablo Neira Ayuso --- src/netlink_linearize.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'src/netlink_linearize.c') diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c index 8471e837..aa00564a 100644 --- a/src/netlink_linearize.c +++ b/src/netlink_linearize.c @@ -1071,6 +1071,45 @@ static void netlink_gen_nat_stmt(struct netlink_linearize_ctx *ctx, nftnl_rule_add_expr(ctx->nlr, nle); } +static void netlink_gen_tproxy_stmt(struct netlink_linearize_ctx *ctx, + const struct stmt *stmt) +{ + struct nftnl_expr *nle; + enum nft_registers addr_reg; + enum nft_registers port_reg; + int registers = 0; + const int family = stmt->tproxy.family; + int nftnl_reg_port; + + nle = alloc_nft_expr("tproxy"); + + nftnl_expr_set_u32(nle, NFTNL_EXPR_TPROXY_FAMILY, family); + + nftnl_reg_port = NFTNL_EXPR_TPROXY_REG_PORT; + + if (stmt->tproxy.addr) { + addr_reg = get_register(ctx, NULL); + registers++; + netlink_gen_expr(ctx, stmt->tproxy.addr, addr_reg); + netlink_put_register(nle, NFTNL_EXPR_TPROXY_REG_ADDR, + addr_reg); + } + + if (stmt->tproxy.port) { + port_reg = get_register(ctx, NULL); + registers++; + netlink_gen_expr(ctx, stmt->tproxy.port, port_reg); + netlink_put_register(nle, nftnl_reg_port, port_reg); + } + + while (registers > 0) { + release_register(ctx, NULL); + registers--; + } + + nftnl_rule_add_expr(ctx->nlr, nle); +} + static void netlink_gen_dup_stmt(struct netlink_linearize_ctx *ctx, const struct stmt *stmt) { @@ -1301,6 +1340,8 @@ static void netlink_gen_stmt(struct netlink_linearize_ctx *ctx, return netlink_gen_reject_stmt(ctx, stmt); case STMT_NAT: return netlink_gen_nat_stmt(ctx, stmt); + case STMT_TPROXY: + return netlink_gen_tproxy_stmt(ctx, stmt); case STMT_DUP: return netlink_gen_dup_stmt(ctx, stmt); case STMT_QUEUE: -- cgit v1.2.3