mptcp: add support for port based endpoint

The feature is supported by the kernel since 5.11-net-next,
let's allow user-space to use it.

Just parse and dump an additional, per endpoint, u16 attribute

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David Ahern <dsahern@kernel.org>

diff --git a/ip/ipmptcp.c b/ip/ipmptcp.c
index e1ffafb3c658b5c341879c15e5702d84018c5eaf..5f659b598c900e8279df7b07e44a1a1a4bd6eae6 100644 (file)
--- a/ip/ipmptcp.c
+++ b/ip/ipmptcp.c
@@ -17,7 +17,7 @@ static void usage(void)
 {
        fprintf(stderr,
                "Usage: ip mptcp endpoint add ADDRESS [ dev NAME ] [ id ID ]\n"
-               "                                     [ FLAG-LIST ]\n"
+               "                                     [ port NR ] [ FLAG-LIST ]\n"
                "       ip mptcp endpoint delete id ID\n"
                "       ip mptcp endpoint show [ id ID ]\n"
                "       ip mptcp endpoint flush\n"
@@ -97,6 +97,7 @@ static int mptcp_parse_opt(int argc, char **argv, struct nlmsghdr *n,
        bool id_set = false;
        __u32 index = 0;
        __u32 flags = 0;
+       __u16 port = 0;
        __u8 id = 0;
 
        ll_init_map(&rth);
@@ -123,6 +124,10 @@ static int mptcp_parse_opt(int argc, char **argv, struct nlmsghdr *n,
                        if (!index)
                                invarg("device does not exist\n", ifname);
 
+               } else if (matches(*argv, "port") == 0) {
+                       NEXT_ARG();
+                       if (get_u16(&port, *argv, 0))
+                               invarg("expected port", *argv);
                } else if (get_addr(&address, *argv, AF_UNSPEC) == 0) {
                        addr_set = true;
                } else {
@@ -145,6 +150,8 @@ static int mptcp_parse_opt(int argc, char **argv, struct nlmsghdr *n,
                addattr32(n, MPTCP_BUFLEN, MPTCP_PM_ADDR_ATTR_FLAGS, flags);
        if (index)
                addattr32(n, MPTCP_BUFLEN, MPTCP_PM_ADDR_ATTR_IF_IDX, index);
+       if (port)
+               addattr16(n, MPTCP_BUFLEN, MPTCP_PM_ADDR_ATTR_PORT, port);
        if (addr_set) {
                int type;
 
@@ -181,8 +188,8 @@ static int print_mptcp_addrinfo(struct rtattr *addrinfo)
        __u8 family = AF_UNSPEC, addr_attr_type;
        const char *ifname;
        unsigned int flags;
+       __u16 id, port;
        int index;
-       __u16 id;
 
        parse_rtattr_nested(tb, MPTCP_PM_ADDR_ATTR_MAX, addrinfo);
 
@@ -196,6 +203,11 @@ static int print_mptcp_addrinfo(struct rtattr *addrinfo)
                print_string(PRINT_ANY, "address", "%s ",
                             format_host_rta(family, tb[addr_attr_type]));
        }
+       if (tb[MPTCP_PM_ADDR_ATTR_PORT]) {
+               port = rta_getattr_u16(tb[MPTCP_PM_ADDR_ATTR_PORT]);
+               if (port)
+                       print_uint(PRINT_ANY, "port", "port %u ", port);
+       }
        if (tb[MPTCP_PM_ADDR_ATTR_ID]) {
                id = rta_getattr_u8(tb[MPTCP_PM_ADDR_ATTR_ID]);
                print_uint(PRINT_ANY, "id", "id %u ", id);

diff --git a/man/man8/ip-mptcp.8 b/man/man8/ip-mptcp.8
index ef8409ea4a24df631656f85e878f5bb805ea21a2..98cb93b9c595a4ee0d9e56228e8fb178acc0e230 100644 (file)
--- a/man/man8/ip-mptcp.8
+++ b/man/man8/ip-mptcp.8
@@ -20,6 +20,8 @@ ip-mptcp \- MPTCP path manager configuration
 .ti -8
 .BR "ip mptcp endpoint add "
 .IR IFADDR
+.RB "[ " port
+.IR PORT " ]"
 .RB "[ " dev
 .IR IFNAME " ]"
 .RB "[ " id
@@ -87,6 +89,12 @@ ip mptcp endpoint flush      flush all existing MPTCP endpoints
 .TE
 
 .TP
+.IR PORT
+When a port number is specified, incoming MPTCP subflows for already
+established MPTCP sockets will be accepted on the specified port, regardless
+the original listener port accepting the first MPTCP subflow and/or
+this peer being actually on the client side.
+
 .IR ID
 is a unique numeric identifier for the given endpoint