bird/nest/iface.c
Ondrej Zajicek (work) 943478b00f Basic VRF support
Add basic VRF (virtual routing and forwarding) support. Protocols can be
associated with VRFs, such protocols will be restricted to interfaces
assigned to the VRF (as reported by Linux kernel) and will use sockets
bound to the VRF. E.g., different multihop BGP instances can use diffent
kernel routing tables to handle BGP TCP connections.

The VRF support is preliminary, currently there are several limitations:

- Recent Linux kernels (4.11) do not handle correctly sockets bound
to interaces that are part of VRF, so most protocols other than multihop
BGP do not work. This will be fixed by future kernel versions.

- Neighbor cache ignores VRFs. Breaks config with the same prefix on
local interfaces in different VRFs. Not much problem as single hop
protocols do not work anyways.

- Olock code ignores VRFs. Breaks config with multiple BGP peers with the
same IP address in different VRFs.

- Incoming BGP connections are not dispatched according to VRFs.
Breaks config with multiple BGP peers with the same IP address in
different VRFs. Perhaps we would need some kernel API to read VRF of
incoming connection? Or probably use multiple listening sockets in
int-new branch.

- We should handle master VRF interface up/down events and perhaps
disable associated protocols when VRF goes down. Or at least disable
associated interfaces.

- Also we should check if the master iface is really VRF iface and
not some other kind of master iface.

- BFD session request dispatch should be aware of VRFs.

- Perhaps kernel protocol should read default kernel table ID from VRF
iface so it is not necessary to configure it.

- Perhaps we should have per-VRF default table.
2017-09-06 17:38:48 +02:00

822 lines
18 KiB
C

/*
* BIRD -- Management of Interfaces and Neighbor Cache
*
* (c) 1998--2000 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
/**
* DOC: Interfaces
*
* The interface module keeps track of all network interfaces in the
* system and their addresses.
*
* Each interface is represented by an &iface structure which carries
* interface capability flags (%IF_MULTIACCESS, %IF_BROADCAST etc.),
* MTU, interface name and index and finally a linked list of network
* prefixes assigned to the interface, each one represented by
* struct &ifa.
*
* The interface module keeps a `soft-up' state for each &iface which
* is a conjunction of link being up, the interface being of a `sane'
* type and at least one IP address assigned to it.
*/
#undef LOCAL_DEBUG
#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/cli.h"
#include "lib/resource.h"
#include "lib/string.h"
#include "conf/conf.h"
static pool *if_pool;
list iface_list;
/**
* ifa_dump - dump interface address
* @a: interface address descriptor
*
* This function dumps contents of an &ifa to the debug output.
*/
void
ifa_dump(struct ifa *a)
{
debug("\t%I, net %I/%-2d bc %I -> %I%s%s%s\n", a->ip, a->prefix, a->pxlen, a->brd, a->opposite,
(a->flags & IF_UP) ? "" : " DOWN",
(a->flags & IA_PRIMARY) ? "" : " SEC",
(a->flags & IA_PEER) ? "PEER" : "");
}
/**
* if_dump - dump interface
* @i: interface to dump
*
* This function dumps all information associated with a given
* network interface to the debug output.
*/
void
if_dump(struct iface *i)
{
struct ifa *a;
debug("IF%d: %s", i->index, i->name);
if (i->flags & IF_SHUTDOWN)
debug(" SHUTDOWN");
if (i->flags & IF_UP)
debug(" UP");
else
debug(" DOWN");
if (i->flags & IF_ADMIN_UP)
debug(" LINK-UP");
if (i->flags & IF_MULTIACCESS)
debug(" MA");
if (i->flags & IF_BROADCAST)
debug(" BC");
if (i->flags & IF_MULTICAST)
debug(" MC");
if (i->flags & IF_LOOPBACK)
debug(" LOOP");
if (i->flags & IF_IGNORE)
debug(" IGN");
if (i->flags & IF_TMP_DOWN)
debug(" TDOWN");
debug(" MTU=%d\n", i->mtu);
WALK_LIST(a, i->addrs)
{
ifa_dump(a);
ASSERT((a != i->addr) == !(a->flags & IA_PRIMARY));
}
}
/**
* if_dump_all - dump all interfaces
*
* This function dumps information about all known network
* interfaces to the debug output.
*/
void
if_dump_all(void)
{
struct iface *i;
debug("Known network interfaces:\n");
WALK_LIST(i, iface_list)
if_dump(i);
debug("Router ID: %08x\n", config->router_id);
}
static inline unsigned
if_what_changed(struct iface *i, struct iface *j)
{
unsigned c;
if (((i->flags ^ j->flags) & ~(IF_UP | IF_SHUTDOWN | IF_UPDATED | IF_ADMIN_UP | IF_LINK_UP | IF_TMP_DOWN | IF_JUST_CREATED))
|| (i->index != j->index) || (i->master != j->master))
return IF_CHANGE_TOO_MUCH;
c = 0;
if ((i->flags ^ j->flags) & IF_UP)
c |= (i->flags & IF_UP) ? IF_CHANGE_DOWN : IF_CHANGE_UP;
if ((i->flags ^ j->flags) & IF_LINK_UP)
c |= IF_CHANGE_LINK;
if (i->mtu != j->mtu)
c |= IF_CHANGE_MTU;
return c;
}
static inline void
if_copy(struct iface *to, struct iface *from)
{
to->flags = from->flags | (to->flags & IF_TMP_DOWN);
to->mtu = from->mtu;
to->master_index = from->master_index;
to->master = from->master;
}
static inline void
ifa_send_notify(struct proto *p, unsigned c, struct ifa *a)
{
if (p->ifa_notify && (!p->vrf || p->vrf == a->iface->master))
{
if (p->debug & D_IFACES)
log(L_TRACE "%s <%s address %I/%d on interface %s %s",
p->name, (a->flags & IA_PRIMARY) ? " primary" : "",
a->prefix, a->pxlen, a->iface->name,
(c & IF_CHANGE_UP) ? "added" : "removed");
p->ifa_notify(p, c, a);
}
}
static void
ifa_notify_change_(unsigned c, struct ifa *a)
{
struct proto *p;
DBG("IFA change notification (%x) for %s:%I\n", c, a->iface->name, a->ip);
WALK_LIST(p, active_proto_list)
ifa_send_notify(p, c, a);
}
static inline void
ifa_notify_change(unsigned c, struct ifa *a)
{
if (c & IF_CHANGE_DOWN)
neigh_ifa_update(a);
ifa_notify_change_(c, a);
if (c & IF_CHANGE_UP)
neigh_ifa_update(a);
}
static inline void
if_send_notify(struct proto *p, unsigned c, struct iface *i)
{
if (p->if_notify && (!p->vrf || p->vrf == i->master))
{
if (p->debug & D_IFACES)
log(L_TRACE "%s < interface %s %s", p->name, i->name,
(c & IF_CHANGE_UP) ? "goes up" :
(c & IF_CHANGE_DOWN) ? "goes down" :
(c & IF_CHANGE_MTU) ? "changes MTU" :
(c & IF_CHANGE_LINK) ? "changes link" :
(c & IF_CHANGE_CREATE) ? "created" :
"sends unknown event");
p->if_notify(p, c, i);
}
}
static void
if_notify_change(unsigned c, struct iface *i)
{
struct proto *p;
struct ifa *a;
if (i->flags & IF_JUST_CREATED)
{
i->flags &= ~IF_JUST_CREATED;
c |= IF_CHANGE_CREATE | IF_CHANGE_MTU;
}
DBG("Interface change notification (%x) for %s\n", c, i->name);
#ifdef LOCAL_DEBUG
if_dump(i);
#endif
if (c & IF_CHANGE_DOWN)
neigh_if_down(i);
if (c & IF_CHANGE_DOWN)
WALK_LIST(a, i->addrs)
{
a->flags = (i->flags & ~IA_FLAGS) | (a->flags & IA_FLAGS);
ifa_notify_change_(IF_CHANGE_DOWN, a);
}
WALK_LIST(p, active_proto_list)
if_send_notify(p, c, i);
if (c & IF_CHANGE_UP)
WALK_LIST(a, i->addrs)
{
a->flags = (i->flags & ~IA_FLAGS) | (a->flags & IA_FLAGS);
ifa_notify_change_(IF_CHANGE_UP, a);
}
if (c & IF_CHANGE_UP)
neigh_if_up(i);
if ((c & (IF_CHANGE_UP | IF_CHANGE_DOWN | IF_CHANGE_LINK)) == IF_CHANGE_LINK)
neigh_if_link(i);
}
static unsigned
if_recalc_flags(struct iface *i, unsigned flags)
{
if ((flags & (IF_SHUTDOWN | IF_TMP_DOWN)) ||
!(flags & IF_ADMIN_UP) ||
!i->addr ||
(i->master_index && !i->master))
flags &= ~IF_UP;
else
flags |= IF_UP;
return flags;
}
static void
if_change_flags(struct iface *i, unsigned flags)
{
unsigned of = i->flags;
i->flags = if_recalc_flags(i, flags);
if ((i->flags ^ of) & IF_UP)
if_notify_change((i->flags & IF_UP) ? IF_CHANGE_UP : IF_CHANGE_DOWN, i);
}
/**
* if_delete - remove interface
* @old: interface
*
* This function is called by the low-level platform dependent code
* whenever it notices an interface disappears. It is just a shorthand
* for if_update().
*/
void
if_delete(struct iface *old)
{
struct iface f = {};
strncpy(f.name, old->name, sizeof(f.name)-1);
f.flags = IF_SHUTDOWN;
if_update(&f);
}
/**
* if_update - update interface status
* @new: new interface status
*
* if_update() is called by the low-level platform dependent code
* whenever it notices an interface change.
*
* There exist two types of interface updates -- synchronous and asynchronous
* ones. In the synchronous case, the low-level code calls if_start_update(),
* scans all interfaces reported by the OS, uses if_update() and ifa_update()
* to pass them to the core and then it finishes the update sequence by
* calling if_end_update(). When working asynchronously, the sysdep code
* calls if_update() and ifa_update() whenever it notices a change.
*
* if_update() will automatically notify all other modules about the change.
*/
struct iface *
if_update(struct iface *new)
{
struct iface *i;
unsigned c;
WALK_LIST(i, iface_list)
if (!strcmp(new->name, i->name))
{
new->addr = i->addr;
new->flags = if_recalc_flags(new, new->flags);
c = if_what_changed(i, new);
if (c & IF_CHANGE_TOO_MUCH) /* Changed a lot, convert it to down/up */
{
DBG("Interface %s changed too much -- forcing down/up transition\n", i->name);
if_change_flags(i, i->flags | IF_TMP_DOWN);
rem_node(&i->n);
new->addr = i->addr;
memcpy(&new->addrs, &i->addrs, sizeof(i->addrs));
memcpy(i, new, sizeof(*i));
i->flags &= ~IF_UP; /* IF_TMP_DOWN will be added later */
goto newif;
}
if_copy(i, new);
if (c)
if_notify_change(c, i);
i->flags |= IF_UPDATED;
return i;
}
i = mb_alloc(if_pool, sizeof(struct iface));
memcpy(i, new, sizeof(*i));
init_list(&i->addrs);
newif:
init_list(&i->neighbors);
i->flags |= IF_UPDATED | IF_TMP_DOWN; /* Tmp down as we don't have addresses yet */
add_tail(&iface_list, &i->n);
return i;
}
void
if_start_update(void)
{
struct iface *i;
struct ifa *a;
WALK_LIST(i, iface_list)
{
i->flags &= ~IF_UPDATED;
WALK_LIST(a, i->addrs)
a->flags &= ~IF_UPDATED;
}
}
void
if_end_partial_update(struct iface *i)
{
if (i->flags & IF_TMP_DOWN)
if_change_flags(i, i->flags & ~IF_TMP_DOWN);
}
void
if_end_update(void)
{
struct iface *i;
struct ifa *a, *b;
WALK_LIST(i, iface_list)
{
if (!(i->flags & IF_UPDATED))
if_change_flags(i, (i->flags & ~IF_ADMIN_UP) | IF_SHUTDOWN);
else
{
WALK_LIST_DELSAFE(a, b, i->addrs)
if (!(a->flags & IF_UPDATED))
ifa_delete(a);
if_end_partial_update(i);
}
}
}
void
if_flush_ifaces(struct proto *p)
{
if (p->debug & D_EVENTS)
log(L_TRACE "%s: Flushing interfaces", p->name);
if_start_update();
if_end_update();
}
/**
* if_feed_baby - advertise interfaces to a new protocol
* @p: protocol to feed
*
* When a new protocol starts, this function sends it a series
* of notifications about all existing interfaces.
*/
void
if_feed_baby(struct proto *p)
{
struct iface *i;
struct ifa *a;
if (!p->if_notify && !p->ifa_notify) /* shortcut */
return;
DBG("Announcing interfaces to new protocol %s\n", p->name);
WALK_LIST(i, iface_list)
{
if_send_notify(p, IF_CHANGE_CREATE | ((i->flags & IF_UP) ? IF_CHANGE_UP : 0), i);
if (i->flags & IF_UP)
WALK_LIST(a, i->addrs)
ifa_send_notify(p, IF_CHANGE_CREATE | IF_CHANGE_UP, a);
}
}
/**
* if_find_by_index - find interface by ifindex
* @idx: ifindex
*
* This function finds an &iface structure corresponding to an interface
* of the given index @idx. Returns a pointer to the structure or %NULL
* if no such structure exists.
*/
struct iface *
if_find_by_index(unsigned idx)
{
struct iface *i;
WALK_LIST(i, iface_list)
if (i->index == idx && !(i->flags & IF_SHUTDOWN))
return i;
return NULL;
}
/**
* if_find_by_name - find interface by name
* @name: interface name
*
* This function finds an &iface structure corresponding to an interface
* of the given name @name. Returns a pointer to the structure or %NULL
* if no such structure exists.
*/
struct iface *
if_find_by_name(char *name)
{
struct iface *i;
WALK_LIST(i, iface_list)
if (!strcmp(i->name, name))
return i;
return NULL;
}
struct iface *
if_get_by_name(char *name)
{
struct iface *i;
if (i = if_find_by_name(name))
return i;
/* No active iface, create a dummy */
i = mb_allocz(if_pool, sizeof(struct iface));
strncpy(i->name, name, sizeof(i->name)-1);
i->flags = IF_SHUTDOWN;
init_list(&i->addrs);
init_list(&i->neighbors);
add_tail(&iface_list, &i->n);
return i;
}
struct ifa *kif_choose_primary(struct iface *i);
static int
ifa_recalc_primary(struct iface *i)
{
struct ifa *a = kif_choose_primary(i);
if (a == i->addr)
return 0;
if (i->addr)
i->addr->flags &= ~IA_PRIMARY;
if (a)
{
a->flags |= IA_PRIMARY;
rem_node(&a->n);
add_head(&i->addrs, &a->n);
}
i->addr = a;
return 1;
}
void
ifa_recalc_all_primary_addresses(void)
{
struct iface *i;
WALK_LIST(i, iface_list)
{
if (ifa_recalc_primary(i))
if_change_flags(i, i->flags | IF_TMP_DOWN);
}
}
static inline int
ifa_same(struct ifa *a, struct ifa *b)
{
return ipa_equal(a->ip, b->ip) && ipa_equal(a->prefix, b->prefix) &&
a->pxlen == b->pxlen;
}
/**
* ifa_update - update interface address
* @a: new interface address
*
* This function adds address information to a network
* interface. It's called by the platform dependent code during
* the interface update process described under if_update().
*/
struct ifa *
ifa_update(struct ifa *a)
{
struct iface *i = a->iface;
struct ifa *b;
WALK_LIST(b, i->addrs)
if (ifa_same(b, a))
{
if (ipa_equal(b->brd, a->brd) &&
ipa_equal(b->opposite, a->opposite) &&
b->scope == a->scope &&
!((b->flags ^ a->flags) & IA_PEER))
{
b->flags |= IF_UPDATED;
return b;
}
ifa_delete(b);
break;
}
#ifndef IPV6
if ((i->flags & IF_BROADCAST) && !ipa_nonzero(a->brd))
log(L_ERR "Missing broadcast address for interface %s", i->name);
#endif
b = mb_alloc(if_pool, sizeof(struct ifa));
memcpy(b, a, sizeof(struct ifa));
add_tail(&i->addrs, &b->n);
b->flags = (i->flags & ~IA_FLAGS) | (a->flags & IA_FLAGS);
if (ifa_recalc_primary(i))
if_change_flags(i, i->flags | IF_TMP_DOWN);
if (b->flags & IF_UP)
ifa_notify_change(IF_CHANGE_CREATE | IF_CHANGE_UP, b);
return b;
}
/**
* ifa_delete - remove interface address
* @a: interface address
*
* This function removes address information from a network
* interface. It's called by the platform dependent code during
* the interface update process described under if_update().
*/
void
ifa_delete(struct ifa *a)
{
struct iface *i = a->iface;
struct ifa *b;
WALK_LIST(b, i->addrs)
if (ifa_same(b, a))
{
rem_node(&b->n);
if (b->flags & IF_UP)
{
b->flags &= ~IF_UP;
ifa_notify_change(IF_CHANGE_DOWN, b);
}
if (b->flags & IA_PRIMARY)
{
if_change_flags(i, i->flags | IF_TMP_DOWN);
ifa_recalc_primary(i);
}
mb_free(b);
return;
}
}
u32
if_choose_router_id(struct iface_patt *mask UNUSED6, u32 old_id UNUSED6)
{
#ifndef IPV6
struct iface *i;
struct ifa *a, *b;
b = NULL;
WALK_LIST(i, iface_list)
{
if (!(i->flags & IF_ADMIN_UP) ||
(i->flags & IF_SHUTDOWN))
continue;
WALK_LIST(a, i->addrs)
{
if (a->flags & IA_SECONDARY)
continue;
if (a->scope <= SCOPE_LINK)
continue;
/* Check pattern if specified */
if (mask && !iface_patt_match(mask, i, a))
continue;
/* No pattern or pattern matched */
if (!b || ipa_to_u32(a->ip) < ipa_to_u32(b->ip))
b = a;
}
}
if (!b)
return 0;
u32 id = ipa_to_u32(b->ip);
if (id != old_id)
log(L_INFO "Chosen router ID %R according to interface %s", id, b->iface->name);
return id;
#else
return 0;
#endif
}
/**
* if_init - initialize interface module
*
* This function is called during BIRD startup to initialize
* all data structures of the interface module.
*/
void
if_init(void)
{
if_pool = rp_new(&root_pool, "Interfaces");
init_list(&iface_list);
neigh_init(if_pool);
}
/*
* Interface Pattern Lists
*/
int
iface_patt_match(struct iface_patt *ifp, struct iface *i, struct ifa *a)
{
struct iface_patt_node *p;
WALK_LIST(p, ifp->ipn_list)
{
char *t = p->pattern;
int pos = p->positive;
if (t)
{
if (*t == '-')
{
t++;
pos = !pos;
}
if (!patmatch(t, i->name))
continue;
}
if (p->pxlen == 0)
return pos;
if (!a)
continue;
if (ipa_in_net(a->ip, p->prefix, p->pxlen))
return pos;
if ((a->flags & IA_PEER) &&
ipa_in_net(a->opposite, p->prefix, p->pxlen))
return pos;
continue;
}
return 0;
}
struct iface_patt *
iface_patt_find(list *l, struct iface *i, struct ifa *a)
{
struct iface_patt *p;
WALK_LIST(p, *l)
if (iface_patt_match(p, i, a))
return p;
return NULL;
}
static int
iface_plists_equal(struct iface_patt *pa, struct iface_patt *pb)
{
struct iface_patt_node *x, *y;
x = HEAD(pa->ipn_list);
y = HEAD(pb->ipn_list);
while (x->n.next && y->n.next)
{
if ((x->positive != y->positive) ||
(!x->pattern && y->pattern) || /* This nasty lines where written by me... :-( Feela */
(!y->pattern && x->pattern) ||
((x->pattern != y->pattern) && strcmp(x->pattern, y->pattern)) ||
!ipa_equal(x->prefix, y->prefix) ||
(x->pxlen != y->pxlen))
return 0;
x = (void *) x->n.next;
y = (void *) y->n.next;
}
return (!x->n.next && !y->n.next);
}
int
iface_patts_equal(list *a, list *b, int (*comp)(struct iface_patt *, struct iface_patt *))
{
struct iface_patt *x, *y;
x = HEAD(*a);
y = HEAD(*b);
while (x->n.next && y->n.next)
{
if (!iface_plists_equal(x, y) ||
(comp && !comp(x, y)))
return 0;
x = (void *) x->n.next;
y = (void *) y->n.next;
}
return (!x->n.next && !y->n.next);
}
/*
* CLI commands.
*/
static void
if_show_addr(struct ifa *a)
{
byte opp[STD_ADDRESS_P_LENGTH + 16];
if (ipa_nonzero(a->opposite))
bsprintf(opp, ", opposite %I", a->opposite);
else
opp[0] = 0;
cli_msg(-1003, "\t%I/%d (%s%s, scope %s)",
a->ip, a->pxlen,
(a->flags & IA_PRIMARY) ? "Primary" : (a->flags & IA_SECONDARY) ? "Secondary" : "Unselected",
opp, ip_scope_text(a->scope));
}
void
if_show(void)
{
struct iface *i;
struct ifa *a;
char *type;
WALK_LIST(i, iface_list)
{
if (i->flags & IF_SHUTDOWN)
continue;
char mbuf[16 + sizeof(i->name)] = {};
if (i->master)
bsprintf(mbuf, " master=%s", i->master->name);
else if (i->master_index)
bsprintf(mbuf, " master=#%u", i->master_index);
cli_msg(-1001, "%s %s (index=%d%s)", i->name, (i->flags & IF_UP) ? "up" : "DOWN", i->index, mbuf);
if (!(i->flags & IF_MULTIACCESS))
type = "PtP";
else
type = "MultiAccess";
cli_msg(-1004, "\t%s%s%s Admin%s Link%s%s%s MTU=%d",
type,
(i->flags & IF_BROADCAST) ? " Broadcast" : "",
(i->flags & IF_MULTICAST) ? " Multicast" : "",
(i->flags & IF_ADMIN_UP) ? "Up" : "Down",
(i->flags & IF_LINK_UP) ? "Up" : "Down",
(i->flags & IF_LOOPBACK) ? " Loopback" : "",
(i->flags & IF_IGNORE) ? " Ignored" : "",
i->mtu);
if (i->addr)
if_show_addr(i->addr);
WALK_LIST(a, i->addrs)
if (a != i->addr)
if_show_addr(a);
}
cli_msg(0, "");
}
void
if_show_summary(void)
{
struct iface *i;
byte addr[STD_ADDRESS_P_LENGTH + 16];
cli_msg(-2005, "interface state address");
WALK_LIST(i, iface_list)
{
if (i->addr)
bsprintf(addr, "%I/%d", i->addr->ip, i->addr->pxlen);
else
addr[0] = 0;
cli_msg(-1005, "%-9s %-5s %s", i->name, (i->flags & IF_UP) ? "up" : "DOWN", addr);
}
cli_msg(0, "");
}