[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 the mask of XFRMA_SET_MARK(a.k.a. XFRMA_OUTPUT_MARK in 4.18)
It is optional and the kernel default is 0xffffffff

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: a disadavantage of this version: error message would be the same
for the option 'mark' and  'output-mark'
e.g
./ip/ip xfrm state add output-mark 0xZZ mask 0xab proto \
 esp auth digest_null 0 enc cipher_null ''
Error: argument "0xZZ" is wrong: MARK value is invalid

./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 | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/ip/xfrm_state.c b/ip/xfrm_state.c
index ddf784ca..a258a1a5 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;
 
@@ -447,9 +447,7 @@ static int xfrm_state_modify(int cmd, unsigned int flags, 
int argc, char **argv)
                                is_offload = false;
                        }
                } else if (strcmp(*argv, "output-mark") == 0) {
-                       NEXT_ARG();
-                       if (get_u32(&output_mark, *argv, 0))
-                               invarg("value after \"output-mark\" is 
invalid", *argv);
+                       xfrm_parse_mark(&output_mark, &argc, &argv);
                } else if (strcmp(*argv, "if_id") == 0) {
                        NEXT_ARG();
                        if (get_u32(&if_id, *argv, 0))
@@ -741,8 +739,11 @@ 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