linux/net/bridge/br_netlink.c
Thomas Graf 339bf98ffc [NETLINK]: Do precise netlink message allocations where possible
Account for the netlink message header size directly in nlmsg_new()
instead of relying on the caller calculate it correctly.

Replaces error handling of message construction functions when
constructing notifications with bug traps since a failure implies
a bug in calculating the size of the skb.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-12-02 21:22:11 -08:00

209 lines
4.9 KiB
C

/*
* Bridge netlink control interface
*
* Authors:
* Stephen Hemminger <shemminger@osdl.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/rtnetlink.h>
#include <net/netlink.h>
#include "br_private.h"
static inline size_t br_nlmsg_size(void)
{
return NLMSG_ALIGN(sizeof(struct ifinfomsg))
+ nla_total_size(IFNAMSIZ) /* IFLA_IFNAME */
+ nla_total_size(MAX_ADDR_LEN) /* IFLA_ADDRESS */
+ nla_total_size(4) /* IFLA_MASTER */
+ nla_total_size(4) /* IFLA_MTU */
+ nla_total_size(4) /* IFLA_LINK */
+ nla_total_size(1) /* IFLA_OPERSTATE */
+ nla_total_size(1); /* IFLA_PROTINFO */
}
/*
* Create one netlink message for one interface
* Contains port and master info as well as carrier and bridge state.
*/
static int br_fill_ifinfo(struct sk_buff *skb, const struct net_bridge_port *port,
u32 pid, u32 seq, int event, unsigned int flags)
{
const struct net_bridge *br = port->br;
const struct net_device *dev = port->dev;
struct ifinfomsg *r;
struct nlmsghdr *nlh;
unsigned char *b = skb->tail;
u32 mtu = dev->mtu;
u8 operstate = netif_running(dev) ? dev->operstate : IF_OPER_DOWN;
u8 portstate = port->state;
pr_debug("br_fill_info event %d port %s master %s\n",
event, dev->name, br->dev->name);
nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
r = NLMSG_DATA(nlh);
r->ifi_family = AF_BRIDGE;
r->__ifi_pad = 0;
r->ifi_type = dev->type;
r->ifi_index = dev->ifindex;
r->ifi_flags = dev_get_flags(dev);
r->ifi_change = 0;
RTA_PUT(skb, IFLA_IFNAME, strlen(dev->name)+1, dev->name);
RTA_PUT(skb, IFLA_MASTER, sizeof(int), &br->dev->ifindex);
if (dev->addr_len)
RTA_PUT(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr);
RTA_PUT(skb, IFLA_MTU, sizeof(mtu), &mtu);
if (dev->ifindex != dev->iflink)
RTA_PUT(skb, IFLA_LINK, sizeof(int), &dev->iflink);
RTA_PUT(skb, IFLA_OPERSTATE, sizeof(operstate), &operstate);
if (event == RTM_NEWLINK)
RTA_PUT(skb, IFLA_PROTINFO, sizeof(portstate), &portstate);
nlh->nlmsg_len = skb->tail - b;
return skb->len;
nlmsg_failure:
rtattr_failure:
skb_trim(skb, b - skb->data);
return -EINVAL;
}
/*
* Notify listeners of a change in port information
*/
void br_ifinfo_notify(int event, struct net_bridge_port *port)
{
struct sk_buff *skb;
int err = -ENOBUFS;
pr_debug("bridge notify event=%d\n", event);
skb = nlmsg_new(br_nlmsg_size(), GFP_ATOMIC);
if (skb == NULL)
goto errout;
err = br_fill_ifinfo(skb, port, 0, 0, event, 0);
/* failure implies BUG in br_nlmsg_size() */
BUG_ON(err < 0);
err = rtnl_notify(skb, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
errout:
if (err < 0)
rtnl_set_sk_err(RTNLGRP_LINK, err);
}
/*
* Dump information about all ports, in response to GETLINK
*/
static int br_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
{
struct net_device *dev;
int idx;
int s_idx = cb->args[0];
int err = 0;
read_lock(&dev_base_lock);
for (dev = dev_base, idx = 0; dev; dev = dev->next) {
struct net_bridge_port *p = dev->br_port;
/* not a bridge port */
if (!p)
continue;
if (idx < s_idx)
goto cont;
err = br_fill_ifinfo(skb, p, NETLINK_CB(cb->skb).pid,
cb->nlh->nlmsg_seq, RTM_NEWLINK, NLM_F_MULTI);
if (err <= 0)
break;
cont:
++idx;
}
read_unlock(&dev_base_lock);
cb->args[0] = idx;
return skb->len;
}
/*
* Change state of port (ie from forwarding to blocking etc)
* Used by spanning tree in user space.
*/
static int br_rtm_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
struct rtattr **rta = arg;
struct ifinfomsg *ifm = NLMSG_DATA(nlh);
struct net_device *dev;
struct net_bridge_port *p;
u8 new_state;
if (ifm->ifi_family != AF_BRIDGE)
return -EPFNOSUPPORT;
/* Must pass valid state as PROTINFO */
if (rta[IFLA_PROTINFO-1]) {
u8 *pstate = RTA_DATA(rta[IFLA_PROTINFO-1]);
new_state = *pstate;
} else
return -EINVAL;
if (new_state > BR_STATE_BLOCKING)
return -EINVAL;
/* Find bridge port */
dev = __dev_get_by_index(ifm->ifi_index);
if (!dev)
return -ENODEV;
p = dev->br_port;
if (!p)
return -EINVAL;
/* if kernel STP is running, don't allow changes */
if (p->br->stp_enabled)
return -EBUSY;
if (!netif_running(dev))
return -ENETDOWN;
if (!netif_carrier_ok(dev) && new_state != BR_STATE_DISABLED)
return -ENETDOWN;
p->state = new_state;
br_log_state(p);
return 0;
}
static struct rtnetlink_link bridge_rtnetlink_table[RTM_NR_MSGTYPES] = {
[RTM_GETLINK - RTM_BASE] = { .dumpit = br_dump_ifinfo, },
[RTM_SETLINK - RTM_BASE] = { .doit = br_rtm_setlink, },
};
void __init br_netlink_init(void)
{
rtnetlink_links[PF_BRIDGE] = bridge_rtnetlink_table;
}
void __exit br_netlink_fini(void)
{
rtnetlink_links[PF_BRIDGE] = NULL;
}