d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
9b6835f3ab
freebsd-skq/sys/netinet/ip_carp.c
Alexander V. Chernikov 130aebbab0 Further refactor IPv4 interface route creation. 
* Fix bug with /32 aliases introduced in 81728a538d.
* Explicitly document business logic for IPv4 ifa routes.
* Remove remnants of rtinit()
* Deduplicate ifa->route prefix code by moving it into ia_getrtprefix()
* Deduplicate conditional check for ifa_maintain_loopback_route()  by
 moving into ia_need_loopback_route()
* Remove now-unused flags argument from in_addprefix().

Reviewed by:		donner
PR:			252883
Differential Revision:	https://reviews.freebsd.org/D28246
2021-01-21 21:48:49 +00:00

2317 lines
53 KiB
C
Raw Blame History

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2002 Michael Shalayeff.
* Copyright (c) 2003 Ryan McBride.
* Copyright (c) 2011 Gleb Smirnoff <glebius@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_bpf.h"
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/devctl.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/taskqueue.h>
#include <sys/counter.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/if_llatbl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/vnet.h>
#if defined(INET) || defined(INET6)
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/ip_carp.h>
#include <netinet/ip.h>
#include <machine/in_cksum.h>
#endif
#ifdef INET
#include <netinet/ip_var.h>
#include <netinet/if_ether.h>
#endif
#ifdef INET6
#include <netinet/icmp6.h>
#include <netinet/ip6.h>
#include <netinet6/in6_var.h>
#include <netinet6/ip6_var.h>
#include <netinet6/scope6_var.h>
#include <netinet6/nd6.h>
#endif
#include <crypto/sha1.h>
static MALLOC_DEFINE(M_CARP, "CARP", "CARP addresses");
struct carp_softc {
struct ifnet *sc_carpdev; /* Pointer to parent ifnet. */
struct ifaddr **sc_ifas; /* Our ifaddrs. */
struct sockaddr_dl sc_addr; /* Our link level address. */
struct callout sc_ad_tmo; /* Advertising timeout. */
#ifdef INET
struct callout sc_md_tmo; /* Master down timeout. */
#endif
#ifdef INET6
struct callout sc_md6_tmo; /* XXX: Master down timeout. */
#endif
struct mtx sc_mtx;
int sc_vhid;
int sc_advskew;
int sc_advbase;
int sc_naddrs;
int sc_naddrs6;
int sc_ifasiz;
enum { INIT = 0, BACKUP, MASTER } sc_state;
int sc_suppress;
int sc_sendad_errors;
#define CARP_SENDAD_MAX_ERRORS 3
int sc_sendad_success;
#define CARP_SENDAD_MIN_SUCCESS 3
int sc_init_counter;
uint64_t sc_counter;
/* authentication */
#define CARP_HMAC_PAD 64
unsigned char sc_key[CARP_KEY_LEN];
unsigned char sc_pad[CARP_HMAC_PAD];
SHA1_CTX sc_sha1;
TAILQ_ENTRY(carp_softc) sc_list; /* On the carp_if list. */
LIST_ENTRY(carp_softc) sc_next; /* On the global list. */
};
struct carp_if {
#ifdef INET
int cif_naddrs;
#endif
#ifdef INET6
int cif_naddrs6;
#endif
TAILQ_HEAD(, carp_softc) cif_vrs;
#ifdef INET
struct ip_moptions cif_imo;
#endif
#ifdef INET6
struct ip6_moptions cif_im6o;
#endif
struct ifnet *cif_ifp;
struct mtx cif_mtx;
uint32_t cif_flags;
#define CIF_PROMISC 0x00000001
};
#define CARP_INET 0
#define CARP_INET6 1
static int proto_reg[] = {-1, -1};
/*
* Brief design of carp(4).
*
* Any carp-capable ifnet may have a list of carp softcs hanging off
* its ifp->if_carp pointer. Each softc represents one unique virtual
* host id, or vhid. The softc has a back pointer to the ifnet. All
* softcs are joined in a global list, which has quite limited use.
*
* Any interface address that takes part in CARP negotiation has a
* pointer to the softc of its vhid, ifa->ifa_carp. That could be either
* AF_INET or AF_INET6 address.
*
* Although, one can get the softc's backpointer to ifnet and traverse
* through its ifp->if_addrhead queue to find all interface addresses
* involved in CARP, we keep a growable array of ifaddr pointers. This
* allows us to avoid grabbing the IF_ADDR_LOCK() in many traversals that
* do calls into the network stack, thus avoiding LORs.
*
* Locking:
*
* Each softc has a lock sc_mtx. It is used to synchronise carp_input_c(),
* callout-driven events and ioctl()s.
*
* To traverse the list of softcs on an ifnet we use CIF_LOCK() or carp_sx.
* To traverse the global list we use the mutex carp_mtx.
*
* Known issues with locking:
*
* - Sending ad, we put the pointer to the softc in an mtag, and no reference
* counting is done on the softc.
* - On module unload we may race (?) with packet processing thread
* dereferencing our function pointers.
*/
/* Accept incoming CARP packets. */
VNET_DEFINE_STATIC(int, carp_allow) = 1;
#define V_carp_allow VNET(carp_allow)
/* Set DSCP in outgoing CARP packets. */
VNET_DEFINE_STATIC(int, carp_dscp) = 56;
#define V_carp_dscp VNET(carp_dscp)
/* Preempt slower nodes. */
VNET_DEFINE_STATIC(int, carp_preempt) = 0;
#define V_carp_preempt VNET(carp_preempt)
/* Log level. */
VNET_DEFINE_STATIC(int, carp_log) = 1;
#define V_carp_log VNET(carp_log)
/* Global advskew demotion. */
VNET_DEFINE_STATIC(int, carp_demotion) = 0;
#define V_carp_demotion VNET(carp_demotion)
/* Send error demotion factor. */
VNET_DEFINE_STATIC(int, carp_senderr_adj) = CARP_MAXSKEW;
#define V_carp_senderr_adj VNET(carp_senderr_adj)
/* Iface down demotion factor. */
VNET_DEFINE_STATIC(int, carp_ifdown_adj) = CARP_MAXSKEW;
#define V_carp_ifdown_adj VNET(carp_ifdown_adj)
static int carp_allow_sysctl(SYSCTL_HANDLER_ARGS);
static int carp_dscp_sysctl(SYSCTL_HANDLER_ARGS);
static int carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS);
SYSCTL_NODE(_net_inet, IPPROTO_CARP, carp, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"CARP");
SYSCTL_PROC(_net_inet_carp, OID_AUTO, allow,
CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
0, 0, carp_allow_sysctl, "I",
"Accept incoming CARP packets");
SYSCTL_PROC(_net_inet_carp, OID_AUTO, dscp,
CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
0, 0, carp_dscp_sysctl, "I",
"DSCP value for carp packets");
SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(carp_preempt), 0, "High-priority backup preemption mode");
SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(carp_log), 0, "CARP log level");
SYSCTL_PROC(_net_inet_carp, OID_AUTO, demotion,
CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
0, 0, carp_demote_adj_sysctl, "I",
"Adjust demotion factor (skew of advskew)");
SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor,
CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(carp_senderr_adj), 0, "Send error demotion factor adjustment");
SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor,
CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(carp_ifdown_adj), 0,
"Interface down demotion factor adjustment");
VNET_PCPUSTAT_DEFINE(struct carpstats, carpstats);
VNET_PCPUSTAT_SYSINIT(carpstats);
VNET_PCPUSTAT_SYSUNINIT(carpstats);
#define CARPSTATS_ADD(name, val) \
counter_u64_add(VNET(carpstats)[offsetof(struct carpstats, name) / \
sizeof(uint64_t)], (val))
#define CARPSTATS_INC(name) CARPSTATS_ADD(name, 1)
SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats,
carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
#define CARP_LOCK_INIT(sc) mtx_init(&(sc)->sc_mtx, "carp_softc", \
NULL, MTX_DEF)
#define CARP_LOCK_DESTROY(sc) mtx_destroy(&(sc)->sc_mtx)
#define CARP_LOCK_ASSERT(sc) mtx_assert(&(sc)->sc_mtx, MA_OWNED)
#define CARP_LOCK(sc) mtx_lock(&(sc)->sc_mtx)
#define CARP_UNLOCK(sc) mtx_unlock(&(sc)->sc_mtx)
#define CIF_LOCK_INIT(cif) mtx_init(&(cif)->cif_mtx, "carp_if", \
NULL, MTX_DEF)
#define CIF_LOCK_DESTROY(cif) mtx_destroy(&(cif)->cif_mtx)
#define CIF_LOCK_ASSERT(cif) mtx_assert(&(cif)->cif_mtx, MA_OWNED)
#define CIF_LOCK(cif) mtx_lock(&(cif)->cif_mtx)
#define CIF_UNLOCK(cif) mtx_unlock(&(cif)->cif_mtx)
#define CIF_FREE(cif) do { \
CIF_LOCK(cif); \
if (TAILQ_EMPTY(&(cif)->cif_vrs)) \
carp_free_if(cif); \
else \
CIF_UNLOCK(cif); \
} while (0)
#define CARP_LOG(...) do { \
if (V_carp_log > 0) \
log(LOG_INFO, "carp: " __VA_ARGS__); \
} while (0)
#define CARP_DEBUG(...) do { \
if (V_carp_log > 1) \
log(LOG_DEBUG, __VA_ARGS__); \
} while (0)
#define IFNET_FOREACH_IFA(ifp, ifa) \
CK_STAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link) \
if ((ifa)->ifa_carp != NULL)
#define CARP_FOREACH_IFA(sc, ifa) \
CARP_LOCK_ASSERT(sc); \
for (int _i = 0; \
_i < (sc)->sc_naddrs + (sc)->sc_naddrs6 && \
((ifa) = sc->sc_ifas[_i]) != NULL; \
++_i)
#define IFNET_FOREACH_CARP(ifp, sc) \
KASSERT(mtx_owned(&ifp->if_carp->cif_mtx) || \
sx_xlocked(&carp_sx), ("cif_vrs not locked")); \
TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
#define DEMOTE_ADVSKEW(sc) \
(((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ? \
CARP_MAXSKEW : ((sc)->sc_advskew + V_carp_demotion))
static void carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
static struct carp_softc
*carp_alloc(struct ifnet *);
static void carp_destroy(struct carp_softc *);
static struct carp_if
*carp_alloc_if(struct ifnet *);
static void carp_free_if(struct carp_if *);
static void carp_set_state(struct carp_softc *, int, const char* reason);
static void carp_sc_state(struct carp_softc *);
static void carp_setrun(struct carp_softc *, sa_family_t);
static void carp_master_down(void *);
static void carp_master_down_locked(struct carp_softc *,
const char* reason);
static void carp_send_ad(void *);
static void carp_send_ad_locked(struct carp_softc *);
static void carp_addroute(struct carp_softc *);
static void carp_ifa_addroute(struct ifaddr *);
static void carp_delroute(struct carp_softc *);
static void carp_ifa_delroute(struct ifaddr *);
static void carp_send_ad_all(void *, int);
static void carp_demote_adj(int, char *);
static LIST_HEAD(, carp_softc) carp_list;
static struct mtx carp_mtx;
static struct sx carp_sx;
static struct task carp_sendall_task =
TASK_INITIALIZER(0, carp_send_ad_all, NULL);
static void
carp_hmac_prepare(struct carp_softc *sc)
{
uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
uint8_t vhid = sc->sc_vhid & 0xff;
struct ifaddr *ifa;
int i, found;
#ifdef INET
struct in_addr last, cur, in;
#endif
#ifdef INET6
struct in6_addr last6, cur6, in6;
#endif
CARP_LOCK_ASSERT(sc);
/* Compute ipad from key. */
bzero(sc->sc_pad, sizeof(sc->sc_pad));
bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
for (i = 0; i < sizeof(sc->sc_pad); i++)
sc->sc_pad[i] ^= 0x36;
/* Precompute first part of inner hash. */
SHA1Init(&sc->sc_sha1);
SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
#ifdef INET
cur.s_addr = 0;
do {
found = 0;
last = cur;
cur.s_addr = 0xffffffff;
CARP_FOREACH_IFA(sc, ifa) {
in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
if (ifa->ifa_addr->sa_family == AF_INET &&
ntohl(in.s_addr) > ntohl(last.s_addr) &&
ntohl(in.s_addr) < ntohl(cur.s_addr)) {
cur.s_addr = in.s_addr;
found++;
}
}
if (found)
SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
} while (found);
#endif /* INET */
#ifdef INET6
memset(&cur6, 0, sizeof(cur6));
do {
found = 0;
last6 = cur6;
memset(&cur6, 0xff, sizeof(cur6));
CARP_FOREACH_IFA(sc, ifa) {
in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
if (IN6_IS_SCOPE_EMBED(&in6))
in6.s6_addr16[1] = 0;
if (ifa->ifa_addr->sa_family == AF_INET6 &&
memcmp(&in6, &last6, sizeof(in6)) > 0 &&
memcmp(&in6, &cur6, sizeof(in6)) < 0) {
cur6 = in6;
found++;
}
}
if (found)
SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
} while (found);
#endif /* INET6 */
/* convert ipad to opad */
for (i = 0; i < sizeof(sc->sc_pad); i++)
sc->sc_pad[i] ^= 0x36 ^ 0x5c;
}
static void
carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
unsigned char md[20])
{
SHA1_CTX sha1ctx;
CARP_LOCK_ASSERT(sc);
/* fetch first half of inner hash */
bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
SHA1Final(md, &sha1ctx);
/* outer hash */
SHA1Init(&sha1ctx);
SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
SHA1Update(&sha1ctx, md, 20);
SHA1Final(md, &sha1ctx);
}
static int
carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
unsigned char md[20])
{
unsigned char md2[20];
CARP_LOCK_ASSERT(sc);
carp_hmac_generate(sc, counter, md2);
return (bcmp(md, md2, sizeof(md2)));
}
/*
* process input packet.
* we have rearranged checks order compared to the rfc,
* but it seems more efficient this way or not possible otherwise.
*/
#ifdef INET
int
carp_input(struct mbuf **mp, int *offp, int proto)
{
struct mbuf *m = *mp;
struct ip *ip = mtod(m, struct ip *);
struct carp_header *ch;
int iplen, len;
iplen = *offp;
*mp = NULL;
CARPSTATS_INC(carps_ipackets);
if (!V_carp_allow) {
m_freem(m);
return (IPPROTO_DONE);
}
/* verify that the IP TTL is 255. */
if (ip->ip_ttl != CARP_DFLTTL) {
CARPSTATS_INC(carps_badttl);
CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
ip->ip_ttl,
m->m_pkthdr.rcvif->if_xname);
m_freem(m);
return (IPPROTO_DONE);
}
iplen = ip->ip_hl << 2;
if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
CARPSTATS_INC(carps_badlen);
CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
"on %s\n", __func__, m->m_len - sizeof(struct ip),
m->m_pkthdr.rcvif->if_xname);
m_freem(m);
return (IPPROTO_DONE);
}
if (iplen + sizeof(*ch) < m->m_len) {
if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
CARPSTATS_INC(carps_hdrops);
CARP_DEBUG("%s: pullup failed\n", __func__);
return (IPPROTO_DONE);
}
ip = mtod(m, struct ip *);
}
ch = (struct carp_header *)((char *)ip + iplen);
/*
* verify that the received packet length is
* equal to the CARP header
*/
len = iplen + sizeof(*ch);
if (len > m->m_pkthdr.len) {
CARPSTATS_INC(carps_badlen);
CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
m->m_pkthdr.len,
m->m_pkthdr.rcvif->if_xname);
m_freem(m);
return (IPPROTO_DONE);
}
if ((m = m_pullup(m, len)) == NULL) {
CARPSTATS_INC(carps_hdrops);
return (IPPROTO_DONE);
}
ip = mtod(m, struct ip *);
ch = (struct carp_header *)((char *)ip + iplen);
/* verify the CARP checksum */
m->m_data += iplen;
if (in_cksum(m, len - iplen)) {
CARPSTATS_INC(carps_badsum);
CARP_DEBUG("%s: checksum failed on %s\n", __func__,
m->m_pkthdr.rcvif->if_xname);
m_freem(m);
return (IPPROTO_DONE);
}
m->m_data -= iplen;
carp_input_c(m, ch, AF_INET);
return (IPPROTO_DONE);
}
#endif
#ifdef INET6
int
carp6_input(struct mbuf **mp, int *offp, int proto)
{
struct mbuf *m = *mp;
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
struct carp_header *ch;
u_int len;
CARPSTATS_INC(carps_ipackets6);
if (!V_carp_allow) {
m_freem(m);
return (IPPROTO_DONE);
}
/* check if received on a valid carp interface */
if (m->m_pkthdr.rcvif->if_carp == NULL) {
CARPSTATS_INC(carps_badif);
CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
__func__, m->m_pkthdr.rcvif->if_xname);
m_freem(m);
return (IPPROTO_DONE);
}
/* verify that the IP TTL is 255 */
if (ip6->ip6_hlim != CARP_DFLTTL) {
CARPSTATS_INC(carps_badttl);
CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
ip6->ip6_hlim, m->m_pkthdr.rcvif->if_xname);
m_freem(m);
return (IPPROTO_DONE);
}
/* verify that we have a complete carp packet */
if (m->m_len < *offp + sizeof(*ch)) {
len = m->m_len;
m = m_pullup(m, *offp + sizeof(*ch));
if (m == NULL) {
CARPSTATS_INC(carps_badlen);
CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
return (IPPROTO_DONE);
}
}
ch = (struct carp_header *)(mtod(m, char *) + *offp);
/* verify the CARP checksum */
m->m_data += *offp;
if (in_cksum(m, sizeof(*ch))) {
CARPSTATS_INC(carps_badsum);
CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
m->m_pkthdr.rcvif->if_xname);
m_freem(m);
return (IPPROTO_DONE);
}
m->m_data -= *offp;
carp_input_c(m, ch, AF_INET6);
return (IPPROTO_DONE);
}
#endif /* INET6 */
/*
* This routine should not be necessary at all, but some switches
* (VMWare ESX vswitches) can echo our own packets back at us,
* and we must ignore them or they will cause us to drop out of
* MASTER mode.
*
* We cannot catch all cases of network loops. Instead, what we
* do here is catch any packet that arrives with a carp header
* with a VHID of 0, that comes from an address that is our own.
* These packets are by definition "from us" (even if they are from
* a misconfigured host that is pretending to be us).
*
* The VHID test is outside this mini-function.
*/
static int
carp_source_is_self(struct mbuf *m, struct ifaddr *ifa, sa_family_t af)
{
#ifdef INET
struct ip *ip4;
struct in_addr in4;
#endif
#ifdef INET6
struct ip6_hdr *ip6;
struct in6_addr in6;
#endif
switch (af) {
#ifdef INET
case AF_INET:
ip4 = mtod(m, struct ip *);
in4 = ifatoia(ifa)->ia_addr.sin_addr;
return (in4.s_addr == ip4->ip_src.s_addr);
#endif
#ifdef INET6
case AF_INET6:
ip6 = mtod(m, struct ip6_hdr *);
in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
return (memcmp(&in6, &ip6->ip6_src, sizeof(in6)) == 0);
#endif
default:
break;
}
return (0);
}
static void
carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
{
struct ifnet *ifp = m->m_pkthdr.rcvif;
struct ifaddr *ifa, *match;
struct carp_softc *sc;
uint64_t tmp_counter;
struct timeval sc_tv, ch_tv;
int error;
NET_EPOCH_ASSERT();
/*
* Verify that the VHID is valid on the receiving interface.
*
* There should be just one match. If there are none
* the VHID is not valid and we drop the packet. If
* there are multiple VHID matches, take just the first
* one, for compatibility with previous code. While we're
* scanning, check for obvious loops in the network topology
* (these should never happen, and as noted above, we may
* miss real loops; this is just a double-check).
*/
error = 0;
match = NULL;
IFNET_FOREACH_IFA(ifp, ifa) {
if (match == NULL && ifa->ifa_carp != NULL &&
ifa->ifa_addr->sa_family == af &&
ifa->ifa_carp->sc_vhid == ch->carp_vhid)
match = ifa;
if (ch->carp_vhid == 0 && carp_source_is_self(m, ifa, af))
error = ELOOP;
}
ifa = error ? NULL : match;
if (ifa != NULL)
ifa_ref(ifa);
if (ifa == NULL) {
if (error == ELOOP) {
CARP_DEBUG("dropping looped packet on interface %s\n",
ifp->if_xname);
CARPSTATS_INC(carps_badif); /* ??? */
} else {
CARPSTATS_INC(carps_badvhid);
}
m_freem(m);
return;
}
/* verify the CARP version. */
if (ch->carp_version != CARP_VERSION) {
CARPSTATS_INC(carps_badver);
CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
ch->carp_version);
ifa_free(ifa);
m_freem(m);
return;
}
sc = ifa->ifa_carp;
CARP_LOCK(sc);
ifa_free(ifa);
if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
CARPSTATS_INC(carps_badauth);
CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
sc->sc_vhid, ifp->if_xname);
goto out;
}
tmp_counter = ntohl(ch->carp_counter[0]);
tmp_counter = tmp_counter<<32;
tmp_counter += ntohl(ch->carp_counter[1]);
/* XXX Replay protection goes here */
sc->sc_init_counter = 0;
sc->sc_counter = tmp_counter;
sc_tv.tv_sec = sc->sc_advbase;
sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
ch_tv.tv_sec = ch->carp_advbase;
ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
switch (sc->sc_state) {
case INIT:
break;
case MASTER:
/*
* If we receive an advertisement from a master who's going to
* be more frequent than us, go into BACKUP state.
*/
if (timevalcmp(&sc_tv, &ch_tv, >) ||
timevalcmp(&sc_tv, &ch_tv, ==)) {
callout_stop(&sc->sc_ad_tmo);
carp_set_state(sc, BACKUP,
"more frequent advertisement received");
carp_setrun(sc, 0);
carp_delroute(sc);
}
break;
case BACKUP:
/*
* If we're pre-empting masters who advertise slower than us,
* and this one claims to be slower, treat him as down.
*/
if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
carp_master_down_locked(sc,
"preempting a slower master");
break;
}
/*
* If the master is going to advertise at such a low frequency
* that he's guaranteed to time out, we'd might as well just
* treat him as timed out now.
*/
sc_tv.tv_sec = sc->sc_advbase * 3;
if (timevalcmp(&sc_tv, &ch_tv, <)) {
carp_master_down_locked(sc, "master will time out");
break;
}
/*
* Otherwise, we reset the counter and wait for the next
* advertisement.
*/
carp_setrun(sc, af);
break;
}
out:
CARP_UNLOCK(sc);
m_freem(m);
}
static int
carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
{
struct m_tag *mtag;
if (sc->sc_init_counter) {
/* this could also be seconds since unix epoch */
sc->sc_counter = arc4random();
sc->sc_counter = sc->sc_counter << 32;
sc->sc_counter += arc4random();
} else
sc->sc_counter++;
ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
/* Tag packet for carp_output */
if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
M_NOWAIT)) == NULL) {
m_freem(m);
CARPSTATS_INC(carps_onomem);
return (ENOMEM);
}
bcopy(&sc, mtag + 1, sizeof(sc));
m_tag_prepend(m, mtag);
return (0);
}
/*
* To avoid LORs and possible recursions this function shouldn't
* be called directly, but scheduled via taskqueue.
*/
static void
carp_send_ad_all(void *ctx __unused, int pending __unused)
{
struct carp_softc *sc;
struct epoch_tracker et;
NET_EPOCH_ENTER(et);
mtx_lock(&carp_mtx);
LIST_FOREACH(sc, &carp_list, sc_next)
if (sc->sc_state == MASTER) {
CARP_LOCK(sc);
CURVNET_SET(sc->sc_carpdev->if_vnet);
carp_send_ad_locked(sc);
CURVNET_RESTORE();
CARP_UNLOCK(sc);
}
mtx_unlock(&carp_mtx);
NET_EPOCH_EXIT(et);
}
/* Send a periodic advertisement, executed in callout context. */
static void
carp_send_ad(void *v)
{
struct carp_softc *sc = v;
struct epoch_tracker et;
NET_EPOCH_ENTER(et);
CARP_LOCK_ASSERT(sc);
CURVNET_SET(sc->sc_carpdev->if_vnet);
carp_send_ad_locked(sc);
CURVNET_RESTORE();
CARP_UNLOCK(sc);
NET_EPOCH_EXIT(et);
}
static void
carp_send_ad_error(struct carp_softc *sc, int error)
{
if (error) {
if (sc->sc_sendad_errors < INT_MAX)
sc->sc_sendad_errors++;
if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
static const char fmt[] = "send error %d on %s";
char msg[sizeof(fmt) + IFNAMSIZ];
sprintf(msg, fmt, error, sc->sc_carpdev->if_xname);
carp_demote_adj(V_carp_senderr_adj, msg);
}
sc->sc_sendad_success = 0;
} else {
if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS &&
++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
static const char fmt[] = "send ok on %s";
char msg[sizeof(fmt) + IFNAMSIZ];
sprintf(msg, fmt, sc->sc_carpdev->if_xname);
carp_demote_adj(-V_carp_senderr_adj, msg);
sc->sc_sendad_errors = 0;
} else
sc->sc_sendad_errors = 0;
}
}
/*
* Pick the best ifaddr on the given ifp for sending CARP
* advertisements.
*
* "Best" here is defined by ifa_preferred(). This function is much
* much like ifaof_ifpforaddr() except that we just use ifa_preferred().
*
* (This could be simplified to return the actual address, except that
* it has a different format in AF_INET and AF_INET6.)
*/
static struct ifaddr *
carp_best_ifa(int af, struct ifnet *ifp)
{
struct ifaddr *ifa, *best;
NET_EPOCH_ASSERT();
if (af >= AF_MAX)
return (NULL);
best = NULL;
CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
if (ifa->ifa_addr->sa_family == af &&
(best == NULL || ifa_preferred(best, ifa)))
best = ifa;
}
if (best != NULL)
ifa_ref(best);
return (best);
}
static void
carp_send_ad_locked(struct carp_softc *sc)
{
struct carp_header ch;
struct timeval tv;
struct ifaddr *ifa;
struct carp_header *ch_ptr;
struct mbuf *m;
int len, advskew;
NET_EPOCH_ASSERT();
CARP_LOCK_ASSERT(sc);
advskew = DEMOTE_ADVSKEW(sc);
tv.tv_sec = sc->sc_advbase;
tv.tv_usec = advskew * 1000000 / 256;
ch.carp_version = CARP_VERSION;
ch.carp_type = CARP_ADVERTISEMENT;
ch.carp_vhid = sc->sc_vhid;
ch.carp_advbase = sc->sc_advbase;
ch.carp_advskew = advskew;
ch.carp_authlen = 7; /* XXX DEFINE */
ch.carp_pad1 = 0; /* must be zero */
ch.carp_cksum = 0;
/* XXXGL: OpenBSD picks first ifaddr with needed family. */
#ifdef INET
if (sc->sc_naddrs) {
struct ip *ip;
m = m_gethdr(M_NOWAIT, MT_DATA);
if (m == NULL) {
CARPSTATS_INC(carps_onomem);
goto resched;
}
len = sizeof(*ip) + sizeof(ch);
m->m_pkthdr.len = len;
m->m_pkthdr.rcvif = NULL;
m->m_len = len;
M_ALIGN(m, m->m_len);
m->m_flags |= M_MCAST;
ip = mtod(m, struct ip *);
ip->ip_v = IPVERSION;
ip->ip_hl = sizeof(*ip) >> 2;
ip->ip_tos = V_carp_dscp << IPTOS_DSCP_OFFSET;
ip->ip_len = htons(len);
ip->ip_off = htons(IP_DF);
ip->ip_ttl = CARP_DFLTTL;
ip->ip_p = IPPROTO_CARP;
ip->ip_sum = 0;
ip_fillid(ip);
ifa = carp_best_ifa(AF_INET, sc->sc_carpdev);
if (ifa != NULL) {
ip->ip_src.s_addr =
ifatoia(ifa)->ia_addr.sin_addr.s_addr;
ifa_free(ifa);
} else
ip->ip_src.s_addr = 0;
ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
ch_ptr = (struct carp_header *)(&ip[1]);
bcopy(&ch, ch_ptr, sizeof(ch));
if (carp_prepare_ad(m, sc, ch_ptr))
goto resched;
m->m_data += sizeof(*ip);
ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
m->m_data -= sizeof(*ip);
CARPSTATS_INC(carps_opackets);
carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
&sc->sc_carpdev->if_carp->cif_imo, NULL));
}
#endif /* INET */
#ifdef INET6
if (sc->sc_naddrs6) {
struct ip6_hdr *ip6;
m = m_gethdr(M_NOWAIT, MT_DATA);
if (m == NULL) {
CARPSTATS_INC(carps_onomem);
goto resched;
}
len = sizeof(*ip6) + sizeof(ch);
m->m_pkthdr.len = len;
m->m_pkthdr.rcvif = NULL;
m->m_len = len;
M_ALIGN(m, m->m_len);
m->m_flags |= M_MCAST;
ip6 = mtod(m, struct ip6_hdr *);
bzero(ip6, sizeof(*ip6));
ip6->ip6_vfc |= IPV6_VERSION;
/* Traffic class isn't defined in ip6 struct instead
* it gets offset into flowid field */
ip6->ip6_flow |= htonl(V_carp_dscp << (IPV6_FLOWLABEL_LEN +
IPTOS_DSCP_OFFSET));
ip6->ip6_hlim = CARP_DFLTTL;
ip6->ip6_nxt = IPPROTO_CARP;
/* set the source address */
ifa = carp_best_ifa(AF_INET6, sc->sc_carpdev);
if (ifa != NULL) {
bcopy(IFA_IN6(ifa), &ip6->ip6_src,
sizeof(struct in6_addr));
ifa_free(ifa);
} else
/* This should never happen with IPv6. */
bzero(&ip6->ip6_src, sizeof(struct in6_addr));
/* Set the multicast destination. */
ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
ip6->ip6_dst.s6_addr8[15] = 0x12;
if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
m_freem(m);
CARP_DEBUG("%s: in6_setscope failed\n", __func__);
goto resched;
}
ch_ptr = (struct carp_header *)(&ip6[1]);
bcopy(&ch, ch_ptr, sizeof(ch));
if (carp_prepare_ad(m, sc, ch_ptr))
goto resched;
m->m_data += sizeof(*ip6);
ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
m->m_data -= sizeof(*ip6);
CARPSTATS_INC(carps_opackets6);
carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
&sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
}
#endif /* INET6 */
resched:
callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
}
static void
carp_addroute(struct carp_softc *sc)
{
struct ifaddr *ifa;
CARP_FOREACH_IFA(sc, ifa)
carp_ifa_addroute(ifa);
}
static void
carp_ifa_addroute(struct ifaddr *ifa)
{
switch (ifa->ifa_addr->sa_family) {
#ifdef INET
case AF_INET:
in_addprefix(ifatoia(ifa));
ifa_add_loopback_route(ifa,
(struct sockaddr *)&ifatoia(ifa)->ia_addr);
break;
#endif
#ifdef INET6
case AF_INET6:
ifa_add_loopback_route(ifa,
(struct sockaddr *)&ifatoia6(ifa)->ia_addr);
nd6_add_ifa_lle(ifatoia6(ifa));
break;
#endif
}
}
static void
carp_delroute(struct carp_softc *sc)
{
struct ifaddr *ifa;
CARP_FOREACH_IFA(sc, ifa)
carp_ifa_delroute(ifa);
}
static void
carp_ifa_delroute(struct ifaddr *ifa)
{
switch (ifa->ifa_addr->sa_family) {
#ifdef INET
case AF_INET:
ifa_del_loopback_route(ifa,
(struct sockaddr *)&ifatoia(ifa)->ia_addr);
in_scrubprefix(ifatoia(ifa), LLE_STATIC);
break;
#endif
#ifdef INET6
case AF_INET6:
ifa_del_loopback_route(ifa,
(struct sockaddr *)&ifatoia6(ifa)->ia_addr);
nd6_rem_ifa_lle(ifatoia6(ifa), 1);
break;
#endif
}
}
int
carp_master(struct ifaddr *ifa)
{
struct carp_softc *sc = ifa->ifa_carp;
return (sc->sc_state == MASTER);
}
#ifdef INET
/*
* Broadcast a gratuitous ARP request containing
* the virtual router MAC address for each IP address
* associated with the virtual router.
*/
static void
carp_send_arp(struct carp_softc *sc)
{
struct ifaddr *ifa;
struct in_addr addr;
NET_EPOCH_ASSERT();
CARP_FOREACH_IFA(sc, ifa) {
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
arp_announce_ifaddr(sc->sc_carpdev, addr, LLADDR(&sc->sc_addr));
}
}
int
carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
{
struct carp_softc *sc = ifa->ifa_carp;
if (sc->sc_state == MASTER) {
*enaddr = LLADDR(&sc->sc_addr);
return (1);
}
return (0);
}
#endif
#ifdef INET6
static void
carp_send_na(struct carp_softc *sc)
{
static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
struct ifaddr *ifa;
struct in6_addr *in6;
CARP_FOREACH_IFA(sc, ifa) {
if (ifa->ifa_addr->sa_family != AF_INET6)
continue;
in6 = IFA_IN6(ifa);
nd6_na_output(sc->sc_carpdev, &mcast, in6,
ND_NA_FLAG_OVERRIDE, 1, NULL);
DELAY(1000); /* XXX */
}
}
/*
* Returns ifa in case it's a carp address and it is MASTER, or if the address
* matches and is not a carp address. Returns NULL otherwise.
*/
struct ifaddr *
carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
{
struct ifaddr *ifa;
NET_EPOCH_ASSERT();
ifa = NULL;
CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
if (ifa->ifa_addr->sa_family != AF_INET6)
continue;
if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
continue;
if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
ifa = NULL;
else
ifa_ref(ifa);
break;
}
return (ifa);
}
char *
carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
{
struct ifaddr *ifa;
NET_EPOCH_ASSERT();
IFNET_FOREACH_IFA(ifp, ifa)
if (ifa->ifa_addr->sa_family == AF_INET6 &&
IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
struct carp_softc *sc = ifa->ifa_carp;
struct m_tag *mtag;
mtag = m_tag_get(PACKET_TAG_CARP,
sizeof(struct carp_softc *), M_NOWAIT);
if (mtag == NULL)
/* Better a bit than nothing. */
return (LLADDR(&sc->sc_addr));
bcopy(&sc, mtag + 1, sizeof(sc));
m_tag_prepend(m, mtag);
return (LLADDR(&sc->sc_addr));
}
return (NULL);
}
#endif /* INET6 */
int
carp_forus(struct ifnet *ifp, u_char *dhost)
{
struct carp_softc *sc;
uint8_t *ena = dhost;
if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
return (0);
CIF_LOCK(ifp->if_carp);
IFNET_FOREACH_CARP(ifp, sc) {
/*
* CARP_LOCK() is not here, since would protect nothing, but
* cause deadlock with if_bridge, calling this under its lock.
*/
if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
ETHER_ADDR_LEN)) {
CIF_UNLOCK(ifp->if_carp);
return (1);
}
}
CIF_UNLOCK(ifp->if_carp);
return (0);
}
/* Master down timeout event, executed in callout context. */
static void
carp_master_down(void *v)
{
struct carp_softc *sc = v;
struct epoch_tracker et;
NET_EPOCH_ENTER(et);
CARP_LOCK_ASSERT(sc);
CURVNET_SET(sc->sc_carpdev->if_vnet);
if (sc->sc_state == BACKUP) {
carp_master_down_locked(sc, "master timed out");
}
CURVNET_RESTORE();
CARP_UNLOCK(sc);
NET_EPOCH_EXIT(et);
}
static void
carp_master_down_locked(struct carp_softc *sc, const char *reason)
{
NET_EPOCH_ASSERT();
CARP_LOCK_ASSERT(sc);
switch (sc->sc_state) {
case BACKUP:
carp_set_state(sc, MASTER, reason);
carp_send_ad_locked(sc);
#ifdef INET
carp_send_arp(sc);
#endif
#ifdef INET6
carp_send_na(sc);
#endif
carp_setrun(sc, 0);
carp_addroute(sc);
break;
case INIT:
case MASTER:
#ifdef INVARIANTS
panic("carp: VHID %u@%s: master_down event in %s state\n",
sc->sc_vhid,
sc->sc_carpdev->if_xname,
sc->sc_state ? "MASTER" : "INIT");
#endif
break;
}
}
/*
* When in backup state, af indicates whether to reset the master down timer
* for v4 or v6. If it's set to zero, reset the ones which are already pending.
*/
static void
carp_setrun(struct carp_softc *sc, sa_family_t af)
{
struct timeval tv;
CARP_LOCK_ASSERT(sc);
if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
(sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) ||
!V_carp_allow)
return;
switch (sc->sc_state) {
case INIT:
carp_set_state(sc, BACKUP, "initialization complete");
carp_setrun(sc, 0);
break;
case BACKUP:
callout_stop(&sc->sc_ad_tmo);
tv.tv_sec = 3 * sc->sc_advbase;
tv.tv_usec = sc->sc_advskew * 1000000 / 256;
switch (af) {
#ifdef INET
case AF_INET:
callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
carp_master_down, sc);
break;
#endif
#ifdef INET6
case AF_INET6:
callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
carp_master_down, sc);
break;
#endif
default:
#ifdef INET
if (sc->sc_naddrs)
callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
carp_master_down, sc);
#endif
#ifdef INET6
if (sc->sc_naddrs6)
callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
carp_master_down, sc);
#endif
break;
}
break;
case MASTER:
tv.tv_sec = sc->sc_advbase;
tv.tv_usec = sc->sc_advskew * 1000000 / 256;
callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
carp_send_ad, sc);
break;
}
}
/*
* Setup multicast structures.
*/
static int
carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
{
struct ifnet *ifp = cif->cif_ifp;
int error = 0;
switch (sa) {
#ifdef INET
case AF_INET:
{
struct ip_moptions *imo = &cif->cif_imo;
struct in_mfilter *imf;
struct in_addr addr;
if (ip_mfilter_first(&imo->imo_head) != NULL)
return (0);
imf = ip_mfilter_alloc(M_WAITOK, 0, 0);
ip_mfilter_init(&imo->imo_head);
imo->imo_multicast_vif = -1;
addr.s_addr = htonl(INADDR_CARP_GROUP);
if ((error = in_joingroup(ifp, &addr, NULL,
&imf->imf_inm)) != 0) {
ip_mfilter_free(imf);
break;
}
ip_mfilter_insert(&imo->imo_head, imf);
imo->imo_multicast_ifp = ifp;
imo->imo_multicast_ttl = CARP_DFLTTL;
imo->imo_multicast_loop = 0;
break;
}
#endif
#ifdef INET6
case AF_INET6:
{
struct ip6_moptions *im6o = &cif->cif_im6o;
struct in6_mfilter *im6f[2];
struct in6_addr in6;
if (ip6_mfilter_first(&im6o->im6o_head))
return (0);
im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
ip6_mfilter_init(&im6o->im6o_head);
im6o->im6o_multicast_hlim = CARP_DFLTTL;
im6o->im6o_multicast_ifp = ifp;
/* Join IPv6 CARP multicast group. */
bzero(&in6, sizeof(in6));
in6.s6_addr16[0] = htons(0xff02);
in6.s6_addr8[15] = 0x12;
if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
ip6_mfilter_free(im6f[0]);
ip6_mfilter_free(im6f[1]);
break;
}
if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[0]->im6f_in6m, 0)) != 0) {
ip6_mfilter_free(im6f[0]);
ip6_mfilter_free(im6f[1]);
break;
}
/* Join solicited multicast address. */
bzero(&in6, sizeof(in6));
in6.s6_addr16[0] = htons(0xff02);
in6.s6_addr32[1] = 0;
in6.s6_addr32[2] = htonl(1);
in6.s6_addr32[3] = 0;
in6.s6_addr8[12] = 0xff;
if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
ip6_mfilter_free(im6f[0]);
ip6_mfilter_free(im6f[1]);
break;
}
if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[1]->im6f_in6m, 0)) != 0) {
in6_leavegroup(im6f[0]->im6f_in6m, NULL);
ip6_mfilter_free(im6f[0]);
ip6_mfilter_free(im6f[1]);
break;
}
ip6_mfilter_insert(&im6o->im6o_head, im6f[0]);
ip6_mfilter_insert(&im6o->im6o_head, im6f[1]);
break;
}
#endif
}
return (error);
}
/*
* Free multicast structures.
*/
static void
carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
{
#ifdef INET
struct ip_moptions *imo = &cif->cif_imo;
struct in_mfilter *imf;
#endif
#ifdef INET6
struct ip6_moptions *im6o = &cif->cif_im6o;
struct in6_mfilter *im6f;
#endif
sx_assert(&carp_sx, SA_XLOCKED);
switch (sa) {
#ifdef INET
case AF_INET:
if (cif->cif_naddrs != 0)
break;
while ((imf = ip_mfilter_first(&imo->imo_head)) != NULL) {
ip_mfilter_remove(&imo->imo_head, imf);
in_leavegroup(imf->imf_inm, NULL);
ip_mfilter_free(imf);
}
break;
#endif
#ifdef INET6
case AF_INET6:
if (cif->cif_naddrs6 != 0)
break;
while ((im6f = ip6_mfilter_first(&im6o->im6o_head)) != NULL) {
ip6_mfilter_remove(&im6o->im6o_head, im6f);
in6_leavegroup(im6f->im6f_in6m, NULL);
ip6_mfilter_free(im6f);
}
break;
#endif
}
}
int
carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
{
struct m_tag *mtag;
struct carp_softc *sc;
if (!sa)
return (0);
switch (sa->sa_family) {
#ifdef INET
case AF_INET:
break;
#endif
#ifdef INET6
case AF_INET6:
break;
#endif
default:
return (0);
}
mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
if (mtag == NULL)
return (0);
bcopy(mtag + 1, &sc, sizeof(sc));
/* Set the source MAC address to the Virtual Router MAC Address. */
switch (ifp->if_type) {
case IFT_ETHER:
case IFT_BRIDGE:
case IFT_L2VLAN: {
struct ether_header *eh;
eh = mtod(m, struct ether_header *);
eh->ether_shost[0] = 0;
eh->ether_shost[1] = 0;
eh->ether_shost[2] = 0x5e;
eh->ether_shost[3] = 0;
eh->ether_shost[4] = 1;
eh->ether_shost[5] = sc->sc_vhid;
}
break;
default:
printf("%s: carp is not supported for the %d interface type\n",
ifp->if_xname, ifp->if_type);
return (EOPNOTSUPP);
}
return (0);
}
static struct carp_softc*
carp_alloc(struct ifnet *ifp)
{
struct carp_softc *sc;
struct carp_if *cif;
sx_assert(&carp_sx, SA_XLOCKED);
if ((cif = ifp->if_carp) == NULL)
cif = carp_alloc_if(ifp);
sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
sc->sc_advbase = CARP_DFLTINTV;
sc->sc_vhid = -1; /* required setting */
sc->sc_init_counter = 1;
sc->sc_state = INIT;
sc->sc_ifasiz = sizeof(struct ifaddr *);
sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
sc->sc_carpdev = ifp;
CARP_LOCK_INIT(sc);
#ifdef INET
callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
#endif
#ifdef INET6
callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
#endif
callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
CIF_LOCK(cif);
TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
CIF_UNLOCK(cif);
mtx_lock(&carp_mtx);
LIST_INSERT_HEAD(&carp_list, sc, sc_next);
mtx_unlock(&carp_mtx);
return (sc);
}
static void
carp_grow_ifas(struct carp_softc *sc)
{
struct ifaddr **new;
new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
CARP_LOCK(sc);
bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
free(sc->sc_ifas, M_CARP);
sc->sc_ifas = new;
sc->sc_ifasiz *= 2;
CARP_UNLOCK(sc);
}
static void
carp_destroy(struct carp_softc *sc)
{
struct ifnet *ifp = sc->sc_carpdev;
struct carp_if *cif = ifp->if_carp;
sx_assert(&carp_sx, SA_XLOCKED);
if (sc->sc_suppress)
carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
CARP_UNLOCK(sc);
CIF_LOCK(cif);
TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
CIF_UNLOCK(cif);
mtx_lock(&carp_mtx);
LIST_REMOVE(sc, sc_next);
mtx_unlock(&carp_mtx);
callout_drain(&sc->sc_ad_tmo);
#ifdef INET
callout_drain(&sc->sc_md_tmo);
#endif
#ifdef INET6
callout_drain(&sc->sc_md6_tmo);
#endif
CARP_LOCK_DESTROY(sc);
free(sc->sc_ifas, M_CARP);
free(sc, M_CARP);
}
static struct carp_if*
carp_alloc_if(struct ifnet *ifp)
{
struct carp_if *cif;
int error;
cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
if ((error = ifpromisc(ifp, 1)) != 0)
printf("%s: ifpromisc(%s) failed: %d\n",
__func__, ifp->if_xname, error);
else
cif->cif_flags |= CIF_PROMISC;
CIF_LOCK_INIT(cif);
cif->cif_ifp = ifp;
TAILQ_INIT(&cif->cif_vrs);
IF_ADDR_WLOCK(ifp);
ifp->if_carp = cif;
if_ref(ifp);
IF_ADDR_WUNLOCK(ifp);
return (cif);
}
static void
carp_free_if(struct carp_if *cif)
{
struct ifnet *ifp = cif->cif_ifp;
CIF_LOCK_ASSERT(cif);
KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
__func__));
IF_ADDR_WLOCK(ifp);
ifp->if_carp = NULL;
IF_ADDR_WUNLOCK(ifp);
CIF_LOCK_DESTROY(cif);
if (cif->cif_flags & CIF_PROMISC)
ifpromisc(ifp, 0);
if_rele(ifp);
free(cif, M_CARP);
}
static void
carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
{
CARP_LOCK(sc);
carpr->carpr_state = sc->sc_state;
carpr->carpr_vhid = sc->sc_vhid;
carpr->carpr_advbase = sc->sc_advbase;
carpr->carpr_advskew = sc->sc_advskew;
if (priv)
bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
else
bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
CARP_UNLOCK(sc);
}
int
carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
{
struct carpreq carpr;
struct ifnet *ifp;
struct carp_softc *sc = NULL;
int error = 0, locked = 0;
if ((error = copyin(ifr_data_get_ptr(ifr), &carpr, sizeof carpr)))
return (error);
ifp = ifunit_ref(ifr->ifr_name);
if (ifp == NULL)
return (ENXIO);
switch (ifp->if_type) {
case IFT_ETHER:
case IFT_L2VLAN:
case IFT_BRIDGE:
break;
default:
error = EOPNOTSUPP;
goto out;
}
if ((ifp->if_flags & IFF_MULTICAST) == 0) {
error = EADDRNOTAVAIL;
goto out;
}
sx_xlock(&carp_sx);
switch (cmd) {
case SIOCSVH:
if ((error = priv_check(td, PRIV_NETINET_CARP)))
break;
if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
error = EINVAL;
break;
}
if (ifp->if_carp) {
IFNET_FOREACH_CARP(ifp, sc)
if (sc->sc_vhid == carpr.carpr_vhid)
break;
}
if (sc == NULL) {
sc = carp_alloc(ifp);
CARP_LOCK(sc);
sc->sc_vhid = carpr.carpr_vhid;
LLADDR(&sc->sc_addr)[0] = 0;
LLADDR(&sc->sc_addr)[1] = 0;
LLADDR(&sc->sc_addr)[2] = 0x5e;
LLADDR(&sc->sc_addr)[3] = 0;
LLADDR(&sc->sc_addr)[4] = 1;
LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
} else
CARP_LOCK(sc);
locked = 1;
if (carpr.carpr_advbase > 0) {
if (carpr.carpr_advbase > 255 ||
carpr.carpr_advbase < CARP_DFLTINTV) {
error = EINVAL;
break;
}
sc->sc_advbase = carpr.carpr_advbase;
}
if (carpr.carpr_advskew >= 255) {
error = EINVAL;
break;
}
sc->sc_advskew = carpr.carpr_advskew;
if (carpr.carpr_key[0] != '\0') {
bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
carp_hmac_prepare(sc);
}
if (sc->sc_state != INIT &&
carpr.carpr_state != sc->sc_state) {
switch (carpr.carpr_state) {
case BACKUP:
callout_stop(&sc->sc_ad_tmo);
carp_set_state(sc, BACKUP,
"user requested via ifconfig");
carp_setrun(sc, 0);
carp_delroute(sc);
break;
case MASTER:
carp_master_down_locked(sc,
"user requested via ifconfig");
break;
default:
break;
}
}
break;
case SIOCGVH:
{
int priveleged;
if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
error = EINVAL;
break;
}
if (carpr.carpr_count < 1) {
error = EMSGSIZE;
break;
}
if (ifp->if_carp == NULL) {
error = ENOENT;
break;
}
priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
if (carpr.carpr_vhid != 0) {
IFNET_FOREACH_CARP(ifp, sc)
if (sc->sc_vhid == carpr.carpr_vhid)
break;
if (sc == NULL) {
error = ENOENT;
break;
}
carp_carprcp(&carpr, sc, priveleged);
error = copyout(&carpr, ifr_data_get_ptr(ifr),
sizeof(carpr));
} else {
int i, count;
count = 0;
IFNET_FOREACH_CARP(ifp, sc)
count++;
if (count > carpr.carpr_count) {
CIF_UNLOCK(ifp->if_carp);
error = EMSGSIZE;
break;
}
i = 0;
IFNET_FOREACH_CARP(ifp, sc) {
carp_carprcp(&carpr, sc, priveleged);
carpr.carpr_count = count;
error = copyout(&carpr,
(char *)ifr_data_get_ptr(ifr) +
(i * sizeof(carpr)), sizeof(carpr));
if (error) {
CIF_UNLOCK(ifp->if_carp);
break;
}
i++;
}
}
break;
}
default:
error = EINVAL;
}
sx_xunlock(&carp_sx);
out:
if (locked)
CARP_UNLOCK(sc);
if_rele(ifp);
return (error);
}
static int
carp_get_vhid(struct ifaddr *ifa)
{
if (ifa == NULL || ifa->ifa_carp == NULL)
return (0);
return (ifa->ifa_carp->sc_vhid);
}
int
carp_attach(struct ifaddr *ifa, int vhid)
{
struct ifnet *ifp = ifa->ifa_ifp;
struct carp_if *cif = ifp->if_carp;
struct carp_softc *sc;
int index, error;
KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
switch (ifa->ifa_addr->sa_family) {
#ifdef INET
case AF_INET:
#endif
#ifdef INET6
case AF_INET6:
#endif
break;
default:
return (EPROTOTYPE);
}
sx_xlock(&carp_sx);
if (ifp->if_carp == NULL) {
sx_xunlock(&carp_sx);
return (ENOPROTOOPT);
}
IFNET_FOREACH_CARP(ifp, sc)
if (sc->sc_vhid == vhid)
break;
if (sc == NULL) {
sx_xunlock(&carp_sx);
return (ENOENT);
}
error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
if (error) {
CIF_FREE(cif);
sx_xunlock(&carp_sx);
return (error);
}
index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
carp_grow_ifas(sc);
switch (ifa->ifa_addr->sa_family) {
#ifdef INET
case AF_INET:
cif->cif_naddrs++;
sc->sc_naddrs++;
break;
#endif
#ifdef INET6
case AF_INET6:
cif->cif_naddrs6++;
sc->sc_naddrs6++;
break;
#endif
}
ifa_ref(ifa);
CARP_LOCK(sc);
sc->sc_ifas[index - 1] = ifa;
ifa->ifa_carp = sc;
carp_hmac_prepare(sc);
carp_sc_state(sc);
CARP_UNLOCK(sc);
sx_xunlock(&carp_sx);
return (0);
}
void
carp_detach(struct ifaddr *ifa, bool keep_cif)
{
struct ifnet *ifp = ifa->ifa_ifp;
struct carp_if *cif = ifp->if_carp;
struct carp_softc *sc = ifa->ifa_carp;
int i, index;
KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
sx_xlock(&carp_sx);
CARP_LOCK(sc);
/* Shift array. */
index = sc->sc_naddrs + sc->sc_naddrs6;
for (i = 0; i < index; i++)
if (sc->sc_ifas[i] == ifa)
break;
KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
for (; i < index - 1; i++)
sc->sc_ifas[i] = sc->sc_ifas[i+1];
sc->sc_ifas[index - 1] = NULL;
switch (ifa->ifa_addr->sa_family) {
#ifdef INET
case AF_INET:
cif->cif_naddrs--;
sc->sc_naddrs--;
break;
#endif
#ifdef INET6
case AF_INET6:
cif->cif_naddrs6--;
sc->sc_naddrs6--;
break;
#endif
}
carp_ifa_delroute(ifa);
carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
ifa->ifa_carp = NULL;
ifa_free(ifa);
carp_hmac_prepare(sc);
carp_sc_state(sc);
if (!keep_cif && sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
carp_destroy(sc);
else
CARP_UNLOCK(sc);
if (!keep_cif)
CIF_FREE(cif);
sx_xunlock(&carp_sx);
}
static void
carp_set_state(struct carp_softc *sc, int state, const char *reason)
{
CARP_LOCK_ASSERT(sc);
if (sc->sc_state != state) {
const char *carp_states[] = { CARP_STATES };
char subsys[IFNAMSIZ+5];
snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
sc->sc_carpdev->if_xname);
CARP_LOG("%s: %s -> %s (%s)\n", subsys,
carp_states[sc->sc_state], carp_states[state], reason);
sc->sc_state = state;
devctl_notify("CARP", subsys, carp_states[state], NULL);
}
}
static void
carp_linkstate(struct ifnet *ifp)
{
struct carp_softc *sc;
CIF_LOCK(ifp->if_carp);
IFNET_FOREACH_CARP(ifp, sc) {
CARP_LOCK(sc);
carp_sc_state(sc);
CARP_UNLOCK(sc);
}
CIF_UNLOCK(ifp->if_carp);
}
static void
carp_sc_state(struct carp_softc *sc)
{
CARP_LOCK_ASSERT(sc);
if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
!(sc->sc_carpdev->if_flags & IFF_UP) ||
!V_carp_allow) {
callout_stop(&sc->sc_ad_tmo);
#ifdef INET
callout_stop(&sc->sc_md_tmo);
#endif
#ifdef INET6
callout_stop(&sc->sc_md6_tmo);
#endif
carp_set_state(sc, INIT, "hardware interface down");
carp_setrun(sc, 0);
if (!sc->sc_suppress)
carp_demote_adj(V_carp_ifdown_adj, "interface down");
sc->sc_suppress = 1;
} else {
carp_set_state(sc, INIT, "hardware interface up");
carp_setrun(sc, 0);
if (sc->sc_suppress)
carp_demote_adj(-V_carp_ifdown_adj, "interface up");
sc->sc_suppress = 0;
}
}
static void
carp_demote_adj(int adj, char *reason)
{
atomic_add_int(&V_carp_demotion, adj);
CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
}
static int
carp_allow_sysctl(SYSCTL_HANDLER_ARGS)
{
int new, error;
struct carp_softc *sc;
new = V_carp_allow;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error || !req->newptr)
return (error);
if (V_carp_allow != new) {
V_carp_allow = new;
mtx_lock(&carp_mtx);
LIST_FOREACH(sc, &carp_list, sc_next) {
CARP_LOCK(sc);
if (curvnet == sc->sc_carpdev->if_vnet)
carp_sc_state(sc);
CARP_UNLOCK(sc);
}
mtx_unlock(&carp_mtx);
}
return (0);
}
static int
carp_dscp_sysctl(SYSCTL_HANDLER_ARGS)
{
int new, error;
new = V_carp_dscp;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error || !req->newptr)
return (error);
if (new < 0 || new > 63)
return (EINVAL);
V_carp_dscp = new;
return (0);
}
static int
carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
{
int new, error;
new = V_carp_demotion;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error || !req->newptr)
return (error);
carp_demote_adj(new, "sysctl");
return (0);
}
#ifdef INET
extern struct domain inetdomain;
static struct protosw in_carp_protosw = {
.pr_type = SOCK_RAW,
.pr_domain = &inetdomain,
.pr_protocol = IPPROTO_CARP,
.pr_flags = PR_ATOMIC|PR_ADDR,
.pr_input = carp_input,
.pr_output = rip_output,
.pr_ctloutput = rip_ctloutput,
.pr_usrreqs = &rip_usrreqs
};
#endif
#ifdef INET6
extern struct domain inet6domain;
static struct protosw in6_carp_protosw = {
.pr_type = SOCK_RAW,
.pr_domain = &inet6domain,
.pr_protocol = IPPROTO_CARP,
.pr_flags = PR_ATOMIC|PR_ADDR,
.pr_input = carp6_input,
.pr_output = rip6_output,
.pr_ctloutput = rip6_ctloutput,
.pr_usrreqs = &rip6_usrreqs
};
#endif
static void
carp_mod_cleanup(void)
{
#ifdef INET
if (proto_reg[CARP_INET] == 0) {
(void)ipproto_unregister(IPPROTO_CARP);
pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
proto_reg[CARP_INET] = -1;
}
carp_iamatch_p = NULL;
#endif
#ifdef INET6
if (proto_reg[CARP_INET6] == 0) {
(void)ip6proto_unregister(IPPROTO_CARP);
pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
proto_reg[CARP_INET6] = -1;
}
carp_iamatch6_p = NULL;
carp_macmatch6_p = NULL;
#endif
carp_ioctl_p = NULL;
carp_attach_p = NULL;
carp_detach_p = NULL;
carp_get_vhid_p = NULL;
carp_linkstate_p = NULL;
carp_forus_p = NULL;
carp_output_p = NULL;
carp_demote_adj_p = NULL;
carp_master_p = NULL;
mtx_unlock(&carp_mtx);
taskqueue_drain(taskqueue_swi, &carp_sendall_task);
mtx_destroy(&carp_mtx);
sx_destroy(&carp_sx);
}
static int
carp_mod_load(void)
{
int err;
mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
sx_init(&carp_sx, "carp_sx");
LIST_INIT(&carp_list);
carp_get_vhid_p = carp_get_vhid;
carp_forus_p = carp_forus;
carp_output_p = carp_output;
carp_linkstate_p = carp_linkstate;
carp_ioctl_p = carp_ioctl;
carp_attach_p = carp_attach;
carp_detach_p = carp_detach;
carp_demote_adj_p = carp_demote_adj;
carp_master_p = carp_master;
#ifdef INET6
carp_iamatch6_p = carp_iamatch6;
carp_macmatch6_p = carp_macmatch6;
proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
(struct protosw *)&in6_carp_protosw);
if (proto_reg[CARP_INET6]) {
printf("carp: error %d attaching to PF_INET6\n",
proto_reg[CARP_INET6]);
carp_mod_cleanup();
return (proto_reg[CARP_INET6]);
}
err = ip6proto_register(IPPROTO_CARP);
if (err) {
printf("carp: error %d registering with INET6\n", err);
carp_mod_cleanup();
return (err);
}
#endif
#ifdef INET
carp_iamatch_p = carp_iamatch;
proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
if (proto_reg[CARP_INET]) {
printf("carp: error %d attaching to PF_INET\n",
proto_reg[CARP_INET]);
carp_mod_cleanup();
return (proto_reg[CARP_INET]);
}
err = ipproto_register(IPPROTO_CARP);
if (err) {
printf("carp: error %d registering with INET\n", err);
carp_mod_cleanup();
return (err);
}
#endif
return (0);
}
static int
carp_modevent(module_t mod, int type, void *data)
{
switch (type) {
case MOD_LOAD:
return carp_mod_load();
/* NOTREACHED */
case MOD_UNLOAD:
mtx_lock(&carp_mtx);
if (LIST_EMPTY(&carp_list))
carp_mod_cleanup();
else {
mtx_unlock(&carp_mtx);
return (EBUSY);
}
break;
default:
return (EINVAL);
}
return (0);
}
static moduledata_t carp_mod = {
"carp",
carp_modevent,
0
};
DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
Reference in New Issue View Git Blame Copy Permalink