I'd like to share some (beta-quality) patches permitting to create BGP protocol instances dynamically, based on templates.

Main purpose is to get feedback and make them good enough to be integrated into main tree.

Similar feature was implemented by major vendors yeas ago.

Typically it is used in peering setups.

Patches still have some rough edges (see below) but should work^Wnot make bird crash every 5 minutes.

# Set up template with ALL info except and IP address

# In this case we don't have any option to specify interface, so it is specified in

# neighbor part

template bgp bgg {

š š š š debug all;

š š š š local as 4444;

š š š š neighbor fe80::1%em0 as 4443;

š š š š import all;

š š š š export all;

};

# Set up dynamic template with ranges and neighbor mask

# Accepted format (%) values:

# 1..4 - octets in IPv4 address

# 1..8 - hex groups in IPv6 address

# I - full addressš

# format values can be specified more than once in format string

# e.g. "b_x_%4_%I_%4"

dynamic template bgp bgp_int from bgg {

š š š š dynamic template name "b_s%4-%8-%8";

š š š š dynamic allow fe80::f000/112, fe80::f00/116;

};

# You need to have at least one "normal" bgp peer to get listen socket opened

# Example from working system:

# š using šseveral { dynamic template name "b_Vrf1_s%8";šdynamic allow fe80::/64; }

bird> show protocols

name š š proto š štable š šstate šsince š š š info

direct1 šDirect š master š up š š 22:06:05

kernel1 šKernel š master š up š š 22:06:05

device1 šDevice š master š up š š 22:06:05

ospf3 š šOSPF š š master š up š š 22:06:05 š šRunning

b_Vrf2_dc1_c1 BGP š š šVrf2 š š up š š 22:06:06 š šEstablished

b_Vrf1_se48 BGP š š šVrf1 š up š š 22:06:05 š šEstablished

b_Vrf1_se10 BGP š š šVrf1 š up š š 22:06:06 š šEstablished

b_Vrf1_se45 BGP š š šVrf1 š up š š 22:06:06 š šEstablished

b_Vrf1_se60 BGP š š šVrf1 š up š š 22:06:07 š šEstablished

b_Vrf2_se91 BGP š š šVrf2 š š up š š 22:06:08 š šEstablished

Comments on individual patches:

0001 is basic LPM for the f_trie šand is part of aggregator patch

0002 decouples get-proto-from-address function from incoming connection handling. This makes hacking here much simpler (for example, implementing IP hash lookup)

0003 just movesšSYM_MAX_LEN definition to header

0004 moves sizeof(XXX_proto) info inside protocol structure permitting anyone to call proto_config_init() without knowing details

0005 tries to isolate/limit global new_config/cfg_mem variables usage to absolute minimum. Despite the fact that actual BGP patch does not require much more than config_start_edit() / config_stop_edit() implementation, I (after hours of debugging cores) decided to make things more transparent here.

0006 is the actual patch.

Basically, it

* adds SYM_TEMPLATE class

* adds dyn_parent proto_config field to specify parent template

* adds condition-check and copy-dynamic protocol callbacks

* adds runtime config/protocol creation functions to nest

* adds bgp-specific structure to struct config allocated on demandš

Rough edges:

* non-optimized case for IPv6 LL prefixes

* non-optimized peer lookup for existing sessions

* dynamic expire not implemented (next version)

* no docs (next version)

* some bugs, definitely