[PATCH iproute2-next RFC] ip xfrm: support setting XFRMA_SET_MARK_MASK attribute in states

[Antony Antony]

The XFRMA_SET_MARK_MASK attribute can be set in states (4.19+)
It is optional and the kernel default is 0xffffffff
It is the mask of XFRMA_SET_MARK(a.k.a. XFRMA_OUTPUT_MARK in 4.18)

e.g.
./ip/ip xfrm state add output-mark 0x6 mask 0xab proto esp \
 auth digest_null 0 enc cipher_null ''
ip xfrm state
src 0.0.0.0 dst 0.0.0.0
        proto esp spi 0x00000000 reqid 0 mode transport
        replay-window 0
        output-mark 0x6/0xab
        auth-trunc digest_null 0x30 0
        enc ecb(cipher_null)
        anti-replay context: seq 0x0, oseq 0x0, bitmap 0x00000000
        sel src 0.0.0.0/0 dst 0.0.0.0/0

NOTE: I am sending two versions. Is there preference for the next one
over this? A diference is in error message for "mark" and "output-mark"

./ip/ip xfrm state add output-mark 0xZZ mask 0xab proto esp \
 auth digest_null 0 enc cipher_null ''
Error: argument "0xZZ" is wrong: value after "output-mark" is invalid

vs

./ip/ip xfrm state add mark 0xZZ mask 0xab proto esp \
 auth digest_null 0 enc cipher_null ''
Error: argument "0xZZ" is wrong: MARK value is invalid

Signed-off-by: Antony Antony <ant...@phenome.org>
---
 ip/xfrm_state.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/ip/xfrm_state.c b/ip/xfrm_state.c
index ddf784ca..c45d993b 100644
--- a/ip/xfrm_state.c
+++ b/ip/xfrm_state.c
@@ -328,7 +328,7 @@ static int xfrm_state_modify(int cmd, unsigned int flags, 
int argc, char **argv)
                struct xfrm_user_sec_ctx sctx;
                char    str[CTX_BUF_SIZE];
        } ctx = {};
-       __u32 output_mark = 0;
+       struct xfrm_mark output_mark = {0, 0};
        bool is_if_id_set = false;
        __u32 if_id = 0;
 
@@ -403,7 +403,6 @@ static int xfrm_state_modify(int cmd, unsigned int flags, 
int argc, char **argv)
                        coap = *argv;
 
                        NEXT_ARG();
-
                        get_prefix(&coa, *argv, preferred_family);
                        if (coa.family == AF_UNSPEC)
                                invarg("value after \"coa\" has an unrecognized 
address family", *argv);
@@ -448,8 +447,18 @@ static int xfrm_state_modify(int cmd, unsigned int flags, 
int argc, char **argv)
                        }
                } else if (strcmp(*argv, "output-mark") == 0) {
                        NEXT_ARG();
-                       if (get_u32(&output_mark, *argv, 0))
+                       if (get_u32(&output_mark.v, *argv, 0))
                                invarg("value after \"output-mark\" is 
invalid", *argv);
+                       if (argc > 1) {
+                               NEXT_ARG();
+                               if (strcmp(*argv, "mask") == 0) {
+                                       NEXT_ARG();
+                                       if (get_u32(&output_mark.m, *argv, 0))
+                                               invarg("mask value is 
invalid\n", *argv);
+                               } else {
+                                       PREV_ARG();
+                               }
+                       }
                } else if (strcmp(*argv, "if_id") == 0) {
                        NEXT_ARG();
                        if (get_u32(&if_id, *argv, 0))
@@ -741,8 +750,11 @@ static int xfrm_state_modify(int cmd, unsigned int flags, 
int argc, char **argv)
                }
        }
 
-       if (output_mark)
-               addattr32(&req.n, sizeof(req.buf), XFRMA_OUTPUT_MARK, 
output_mark);
+       if (output_mark.v)
+               addattr32(&req.n, sizeof(req.buf), XFRMA_OUTPUT_MARK, 
output_mark.v);
+
+       if (output_mark.m)
+               addattr32(&req.n, sizeof(req.buf), XFRMA_SET_MARK_MASK, 
output_mark.m);
 
        if (rtnl_open_byproto(&rth, 0, NETLINK_XFRM) < 0)
                exit(1);
-- 
2.21.3