Hello
I find that the graceful restart time number configuration can accept 32bits.
bgp_proto GRACEFUL RESTART TIME expr ';' { BGP_CFG->gr_time = $5; }
While in the RFC 4724 section 3 it says the graceful restart time is 12bits
and restart flags is 4bits.
+--------------------------------------------------+
| Restart Flags (4 bits) |
+--------------------------------------------------+
| Restart Time in seconds (12 bits) |
+--------------------------------------------------+
| Address Family Identifier (16 bits) |
+--------------------------------------------------+
| Subsequent Address Family Identifier (8 bits) |
+--------------------------------------------------+
| Flags for Address Family (8 bits) |
+--------------------------------------------------+
so ,when I set the graceful restart time like 32768.，it will cover the gr_flag.
Becasue ,in the bgp_write_capabilites() function ，it first put the gr_time in.
Then use "|" to put gr_flags. This will casue the value in gr_time first four
bits keep in the gr_flags。
put_u16(buf, caps->gr_time);
buf[0] |= caps->gr_flags;
Also ，I have find in RFC 4724，it required gr_flag expect the first bit ,the
remaining bits are reserved and MUST be set to zero by the sender and ignored
by the receiver. gr_time in the configure also can change the remaining
bits. Meanwhile, in the bgp_read_capabilites() function, it use "& 0xf0" will
remain the wrong 4 bits.
caps->gr_flags = pos[2] & 0xf0;
caps->gr_time = get_u16(pos + 2) & 0x0fff;
I try this on the bird 2.0.7
Thanks
Jingting
Chen
