bgpd: fix route-map comments

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
bgpd: implement "next-hop-self all"

As specified in:
http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/command/irg-cr-book/bgp-m1.html#wp4972925610

This allows overriding next-hop for ibgp learned routes on an
RR for reflected routes.

Especially useful for using iBGP in DMVPN setups. See:
http://blog.ipspace.net/2014/04/changes-in-ibgp-next-hop-processing.html

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
bgpd: route-map: share aspath object compilation code where possible

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
bgpd: merge branch tteras/master~3 (b304dcb)

route-map tidying + next-hop-self all

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
bgpd: fix some bgp_update_main() attribute leaks

bgp_update_main() wasn't doing anything to release attribute values
set from route maps for two of its error paths.  To fix, pull up the
appropriate cleanup from further down and apply it here.

bgp_update_rsclient() doesn't have the issue since it immediately
does bgp_attr_intern() on the results from bgp_{export,import}_modifier.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
bgpd: remove duplicate route-map extcommunity code

route_set_ecommunity_rt and _soo share almost all of their code.
Let's remove one of the redundant copies.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
bgpd: fix double free after extcommunity set (BZ#799)

The route-map extcommunity set code was incorrectly assuming that it
owns the intern'd struct ecommunity reference.  In reality, the intern'd
reference belongs to bgp_update_receive() and we're not supposed to
touch it in the route-map code.

Instead, like all the other set commands, we use a on-heap but
non-intern'd ecommunity to set the new value.  This is then either
intern'd in bgp_update_main/_rsclient() through bgp_attr_intern(), or
free'd through bgp_attr_flush().

This fixes Bugzilla #799, which is that bgpd otherwise crashes with a
double free.  The ecommunity got unintern'd first in the route-map set
command, then in bgp_update_receive().

Debugged-by: Milan Kocian <milon@wq.cz>
Reported-by: Florian S <florian@herrenlohe.de>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
bgpd: fix memory leak on malformed attribute

When bgp_attr_parse returns BGP_ATTR_PARSE_ERROR, it may already have
parsed and allocated some attributes before hitting that error.  Free
the attr's data before returning.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
bgpd: fix IP endianness in debug message

inet_ntop expects network byte order.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
bgpd: don't send NOTIFY twice for malformed attrs

Most of the attribute parsing functions were already sending a notify,
let's clean up the code to make it happen only once.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
*: merge branch stable/0.99.23

bgp extcommunity fixes from stable branch

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>