A major overhaul of the CARP implementation. The ip_carp.c was started

from scratch, copying needed functionality from the old implemenation
on demand, with a thorough review of all code. The main change is that
interface layer has been removed from the CARP. Now redundant addresses
are configured exactly on the interfaces, they run on.

The CARP configuration itself is, as before, configured and read via
SIOCSVH/SIOCGVH ioctls. A new prefix created with SIOCAIFADDR or
SIOCAIFADDR_IN6 may now be configured to a particular virtual host id,
which makes the prefix redundant.

ifconfig(8) semantics has been changed too: now one doesn't need
to clone carpXX interface, he/she should directly configure a vhid
on a Ethernet interface.

To supply vhid data from the kernel to an application the getifaddrs(8)
function had been changed to pass ifam_data with each address. [1]

The new implementation definitely closes all PRs related to carp(4)
being an interface, and may close several others. It also allows
to run a single redundant IP per interface.

Big thanks to Bjoern Zeeb for his help with inet6 part of patch, for
idea on using ifam_data and for several rounds of reviewing!

PR:		kern/117000, kern/126945, kern/126714, kern/120130, kern/117448
Reviewed by:	bz
Submitted by:	bz [1]

1 files changed, 15 insertions, 1 deletions

diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index b2313c0..3520824 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -63,6 +63,7 @@
 
 #include <netinet/in.h>
 #include <netinet/if_ether.h>
+#include <netinet/ip_carp.h>
 #ifdef INET6
 #include <netinet6/scope6_var.h>
 #endif
@@ -83,7 +84,7 @@ struct if_data32 {
 	uint8_t	ifi_addrlen;
 	uint8_t	ifi_hdrlen;
 	uint8_t	ifi_link_state;
-	uint8_t	ifi_spare_char1;
+	uint8_t	ifi_vhid;
 	uint8_t	ifi_spare_char2;
 	uint8_t	ifi_datalen;
 	uint32_t ifi_mtu;
@@ -122,6 +123,9 @@ MALLOC_DEFINE(M_RTABLE, "routetbl", "routing tables");
 static struct	sockaddr route_src = { 2, PF_ROUTE, };
 static struct	sockaddr sa_zero   = { sizeof(sa_zero), AF_INET, };
 
+/* These are external hooks for CARP. */
+int	(*carp_get_vhid_p)(struct ifaddr *);
+
 /*
  * Used by rtsock/raw_input callback code to decide whether to filter the update
  * notification to a socket bound to a particular FIB.
@@ -1508,6 +1512,7 @@ copy_ifdata32(struct if_data *src, struct if_data32 *dst)
 	CP(*src, *dst, ifi_addrlen);
 	CP(*src, *dst, ifi_hdrlen);
 	CP(*src, *dst, ifi_link_state);
+	CP(*src, *dst, ifi_vhid);
 	dst->ifi_datalen = sizeof(struct if_data32);
 	CP(*src, *dst, ifi_mtu);
 	CP(*src, *dst, ifi_metric);
@@ -1559,6 +1564,9 @@ sysctl_iflist(int af, struct walkarg *w)
 				ifm32->ifm_flags = ifp->if_flags |
 				    ifp->if_drv_flags;
 				copy_ifdata32(&ifp->if_data, &ifm32->ifm_data);
+				if (carp_get_vhid_p != NULL)
+					ifm32->ifm_data.ifi_vhid =
+					    (*carp_get_vhid_p)(ifa);
 				ifm32->ifm_addrs = info.rti_addrs;
 				error = SYSCTL_OUT(w->w_req, (caddr_t)ifm32,
 				    len);
@@ -1569,6 +1577,9 @@ sysctl_iflist(int af, struct walkarg *w)
 			ifm->ifm_index = ifp->if_index;
 			ifm->ifm_flags = ifp->if_flags | ifp->if_drv_flags;
 			ifm->ifm_data = ifp->if_data;
+			if (carp_get_vhid_p != NULL)
+				ifm->ifm_data.ifi_vhid =
+				    (*carp_get_vhid_p)(ifa);
 			ifm->ifm_addrs = info.rti_addrs;
 			error = SYSCTL_OUT(w->w_req, (caddr_t)ifm, len);
 #ifdef COMPAT_FREEBSD32
@@ -1595,6 +1606,9 @@ sysctl_iflist(int af, struct walkarg *w)
 				ifam->ifam_flags = ifa->ifa_flags;
 				ifam->ifam_metric = ifa->ifa_metric;
 				ifam->ifam_addrs = info.rti_addrs;
+				if (carp_get_vhid_p != NULL)
+					ifam->ifam_data.ifi_vhid =
+					    (*carp_get_vhid_p)(ifa);
 				error = SYSCTL_OUT(w->w_req, w->w_tmem, len);
 				if (error)
 					goto done;