vty and log: also show local port for RTP conns

Before:

    CONN: (1226/rtp, id:0xD94316AD, ip:127.0.0.2, rtp:2344 rtcp:2345)

After:

    CONN: (1226/rtp C:D94316AD r=127.0.0.2:2344<->l=127.0.0.1:4002)

While changing that string, also include these changes for consistency
and readability:

- use the same r:...<->l:... format as osmo_sock_get_name().
- Instead of 'id:0x' use the actual MGCP format 'C: 9B686BE3'.
- drop the commas
- drop RTCP port: it is always RTP+1 and always an odd number.

Rationale:
The CONN pairs associated with each endpoint show remote RTP
ports. When osmo-mgw is being used by both BSC and MSC, one
side of the pair is showing the internal loop connection inside
osmo-mgw, while my intuition suggested this connection pair
is showing me the RTP port tuple of a single RTP stream. Adding
the local port to the display makes it more clear, IMHO.
Seeing the local port can also help to correlate the MGW vty
dump with a capture of RTP.

Implementation:
I first tried directly using osmo_sock_get_name_buf() on
conn->u.rtp.end.rtp.fd, but that might hide already known information
when the fd is not actively used yet (before SDP): the local address and
port would then be shown from the fd, not from
conn->u.rtp.end.local_addr/_port == hidden before the fd is set up.

Patch-By: whytek, nhofmeyr
Change-Id: Ib89a6779e1d68c6600f00699d4303f6c0ee07132
1 file changed