Hi,
Peter van Dijk pointed me at valgrind. It appears I can improve this
patch a bit more, stay tuned.
Kind regards,
Job
On Thu, Jul 27, 2017 at 05:55:40PM +0200, Job Snijders wrote:
> Hi all,
>
> Here is a patch to decode received BGP shutdown communication messages
> as specified in RFC 8203. In the following example scenario I'm sending
> a shutdown communication with openbgpd:
>
> $ bgpctl neighbor 94.142.241.204 down "TICKET-2331 we are upgrading,
> back in 30 min"
> request processed
>
> And can subsequently observe the message via logging and via 'show protocols
> all':
>
> job@irime:~/source/bird$ sudo ./bird -s test.sock -d -c bird2.conf
> bird: Started
> bird: bgp1: Received: Administrative shutdown: "TICKET-2331 we are
> upgrading, back in 30 min"
>
> job@irime:~/source/bird$ sudo ./birdc -s test.sock show protocols all
> ....
> BGP state: Active
> Neighbor address: 165.254.255.26
> Neighbor AS: 15562
> Connect delay: 3/5
> Last error: Received: Administrative shutdown
> Message: "TICKET-2331 we are upgrading, back in 30 min"
>
> As for the remaining RFC 8203 work:
>
> I could use some help with _sending_ bgp shutdown communication
> messages. It is not clear to me where I should hook the message into
> the config/cli infrastructure. Ideally you can do things like:
>
> $ birdc disable bgp1 "hi, we will upgrade to bird 1.6.4"
>
> or via the configuration (also during reconfigure):
>
> protocol bgp {
> disabled "shutdown due to maintenance ticket 2424";
> description "My BGP uplink";
> local 94.142.241.204 as 65000;
> neighbor 165.254.255.26 as 15562;
> }
>
> Thoughts?
>
> Kind regards,
>
> Job
>
> ---
> proto/bgp/bgp.c | 13 ++++++++++
> proto/bgp/bgp.h | 2 ++
> proto/bgp/packets.c | 73
> ++++++++++++++++++++++++++++++++++-------------------
> 3 files changed, 62 insertions(+), 26 deletions(-)
>
> diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
> index f706e76..551b156 100644
> --- a/proto/bgp/bgp.c
> +++ b/proto/bgp/bgp.c
> @@ -1487,6 +1487,16 @@ bgp_last_errmsg(struct bgp_proto *p)
> }
>
> static const char *
> +bgp_last_shutmsg(struct bgp_proto *p)
> +{
> + unsigned len;
> + char *buf = calloc (128, sizeof (char));
> + len = p->last_received_shutmsg[0];
> + bsnprintf(buf, len, "%s", p->last_received_shutmsg+1);
> + return(buf);
> +}
> +
> +static const char *
> bgp_state_dsc(struct bgp_proto *p)
> {
> if (p->p.proto_state == PS_DOWN)
> @@ -1580,7 +1590,10 @@ bgp_show_proto_info(struct proto *P)
> {
> const char *err1 = bgp_err_classes[p->last_error_class];
> const char *err2 = bgp_last_errmsg(p);
> + const char *msg = bgp_last_shutmsg(p);
> cli_msg(-1006, " Last error: %s%s", err1, err2);
> + if (p->last_received_shutmsg[0] > 0)
> + cli_msg(-1006, " Message: \"%s\"", msg);
> }
> }
>
> diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
> index e47a0eb..d958716 100644
> --- a/proto/bgp/bgp.h
> +++ b/proto/bgp/bgp.h
> @@ -157,6 +157,8 @@ struct bgp_proto {
> u8 last_error_class; /* Error class of last error */
> u32 last_error_code; /* Error code of last error.
> BGP protocol errors
> are encoded as (bgp_err_code << 16 |
> bgp_err_subcode) */
> + byte last_received_shutmsg[129]; /* RFC 8203 */
> +
> #ifdef IPV6
> byte *mp_reach_start, *mp_unreach_start; /* Multiprotocol BGP attribute
> notes */
> unsigned mp_reach_len, mp_unreach_len;
> diff --git a/proto/bgp/packets.c b/proto/bgp/packets.c
> index ab87bdc..1a021dd 100644
> --- a/proto/bgp/packets.c
> +++ b/proto/bgp/packets.c
> @@ -1460,9 +1460,9 @@ static struct {
> { 5, 3, "Unexpected message in Established state" },
> { 6, 0, "Cease" }, /* Subcodes are according to [RFC4486] */
> { 6, 1, "Maximum number of prefixes reached" },
> - { 6, 2, "Administrative shutdown" },
> + { 6, 2, "Administrative shutdown" }, /* RFC 8203 can follow */
> { 6, 3, "Peer de-configured" },
> - { 6, 4, "Administrative reset" },
> + { 6, 4, "Administrative reset" }, /* RFC 8203 can follow */
> { 6, 5, "Connection rejected" },
> { 6, 6, "Other configuration change" },
> { 6, 7, "Connection collision resolution" },
> @@ -1497,35 +1497,56 @@ bgp_error_dsc(unsigned code, unsigned subcode)
> void
> bgp_log_error(struct bgp_proto *p, u8 class, char *msg, unsigned code,
> unsigned subcode, byte *data, unsigned len)
> {
> - const byte *name;
> - byte *t, argbuf[36];
> - unsigned i;
> + const byte *name;
> + byte *t, argbuf[256];
> + unsigned i;
> + unsigned shutdown_comm_length;
>
> - /* Don't report Cease messages generated by myself */
> - if (code == 6 && class == BE_BGP_TX)
> - return;
> + /* Don't report Cease messages generated by myself */
> + if (code == 6 && class == BE_BGP_TX)
> + return;
> +
> + name = bgp_error_dsc(code, subcode);
> + t = argbuf;
> + memset(p->last_received_shutmsg, 0, 129); // clear old RFC 8203 messages
>
> - name = bgp_error_dsc(code, subcode);
> - t = argbuf;
> - if (len)
> + if (len)
> {
> - *t++ = ':';
> - *t++ = ' ';
> + *t++ = ':';
> + *t++ = ' ';
>
> - if ((code == 2) && (subcode == 2) && ((len == 2) || (len == 4)))
> - {
> - /* Bad peer AS - we would like to print the AS */
> - t += bsprintf(t, "%d", (len == 2) ? get_u16(data) : get_u32(data));
> - goto done;
> - }
> - if (len > 16)
> - len = 16;
> - for (i=0; i<len; i++)
> - t += bsprintf(t, "%02x", data[i]);
> + if ((code == 2) && (subcode == 2) && ((len == 2) || (len == 4)))
> + {
> + /* Bad peer AS - we would like to print the AS */
> + t += bsprintf(t, "%d", (len == 2) ? get_u16(data) :
> get_u32(data));
> + goto done;
> + }
> + /* RFC 8203 */
> + if ((code == 6) && ((subcode == 2 || subcode == 4)) && (len <= 129))
> + {
> + shutdown_comm_length = data[0];
> + if ((shutdown_comm_length <= 128) && (len ==
> shutdown_comm_length + 1))
> + {
> + t += bsprintf(t, "\"");
> + for (i=1; i<len; i++)
> + t += bsprintf(t, "%c", data[i]);
> + t += bsprintf(t, "\"");
> + memcpy(p->last_received_shutmsg, data, shutdown_comm_length
> + 1);
> + goto done;
> + }
> + }
> + else
> + {
> + if (len > 16)
> + len = 16;
> + for (i=0; i<len; i++)
> + t += bsprintf(t, "%02x", data[i]);
> + }
> }
> - done:
> - *t = 0;
> - log(L_REMOTE "%s: %s: %s%s", p->p.name, msg, name, argbuf);
> +
> + done:
> + *t = 0;
> + log(L_REMOTE "%s: %s: %s%s", p->p.name, msg, name, argbuf);
> }
>
> static void
