linux/net/core/netpoll.c

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/*
* Common framework for low-level network console, dump, and debugger code
*
* Sep 8 2003 Matt Mackall <mpm@selenic.com>
*
* based on the netconsole code from:
*
* Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
* Copyright (C) 2002 Red Hat, Inc.
*/
#include <linux/smp_lock.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/string.h>
#include <linux/inetdevice.h>
#include <linux/inet.h>
#include <linux/interrupt.h>
#include <linux/netpoll.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/rcupdate.h>
#include <linux/workqueue.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <asm/unaligned.h>
/*
* We maintain a small pool of fully-sized skbs, to make sure the
* message gets out even in extreme OOM situations.
*/
#define MAX_UDP_CHUNK 1460
#define MAX_SKBS 32
#define MAX_QUEUE_DEPTH (MAX_SKBS / 2)
static DEFINE_SPINLOCK(skb_list_lock);
static int nr_skbs;
static struct sk_buff *skbs;
static DEFINE_SPINLOCK(queue_lock);
static int queue_depth;
static struct sk_buff *queue_head, *queue_tail;
static atomic_t trapped;
#define NETPOLL_RX_ENABLED 1
#define NETPOLL_RX_DROP 2
#define MAX_SKB_SIZE \
(MAX_UDP_CHUNK + sizeof(struct udphdr) + \
sizeof(struct iphdr) + sizeof(struct ethhdr))
static void zap_completion_queue(void);
static void queue_process(void *p)
{
unsigned long flags;
struct sk_buff *skb;
while (queue_head) {
spin_lock_irqsave(&queue_lock, flags);
skb = queue_head;
queue_head = skb->next;
if (skb == queue_tail)
queue_head = NULL;
queue_depth--;
spin_unlock_irqrestore(&queue_lock, flags);
dev_queue_xmit(skb);
}
}
static DECLARE_WORK(send_queue, queue_process, NULL);
void netpoll_queue(struct sk_buff *skb)
{
unsigned long flags;
if (queue_depth == MAX_QUEUE_DEPTH) {
__kfree_skb(skb);
return;
}
spin_lock_irqsave(&queue_lock, flags);
if (!queue_head)
queue_head = skb;
else
queue_tail->next = skb;
queue_tail = skb;
queue_depth++;
spin_unlock_irqrestore(&queue_lock, flags);
schedule_work(&send_queue);
}
static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
unsigned short ulen, u32 saddr, u32 daddr)
{
if (uh->check == 0)
return 0;
if (skb->ip_summed == CHECKSUM_HW)
return csum_tcpudp_magic(
saddr, daddr, ulen, IPPROTO_UDP, skb->csum);
skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
return csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
}
/*
* Check whether delayed processing was scheduled for our NIC. If so,
* we attempt to grab the poll lock and use ->poll() to pump the card.
* If this fails, either we've recursed in ->poll() or it's already
* running on another CPU.
*
* Note: we don't mask interrupts with this lock because we're using
* trylock here and interrupts are already disabled in the softirq
* case. Further, we test the poll_owner to avoid recursion on UP
* systems where the lock doesn't exist.
*
* In cases where there is bi-directional communications, reading only
* one message at a time can lead to packets being dropped by the
* network adapter, forcing superfluous retries and possibly timeouts.
* Thus, we set our budget to greater than 1.
*/
static void poll_napi(struct netpoll *np)
{
int budget = 16;
if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
np->poll_owner != smp_processor_id() &&
spin_trylock(&np->poll_lock)) {
np->rx_flags |= NETPOLL_RX_DROP;
atomic_inc(&trapped);
np->dev->poll(np->dev, &budget);
atomic_dec(&trapped);
np->rx_flags &= ~NETPOLL_RX_DROP;
spin_unlock(&np->poll_lock);
}
}
void netpoll_poll(struct netpoll *np)
{
if(!np->dev || !netif_running(np->dev) || !np->dev->poll_controller)
return;
/* Process pending work on NIC */
np->dev->poll_controller(np->dev);
if (np->dev->poll)
poll_napi(np);
zap_completion_queue();
}
static void refill_skbs(void)
{
struct sk_buff *skb;
unsigned long flags;
spin_lock_irqsave(&skb_list_lock, flags);
while (nr_skbs < MAX_SKBS) {
skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
if (!skb)
break;
skb->next = skbs;
skbs = skb;
nr_skbs++;
}
spin_unlock_irqrestore(&skb_list_lock, flags);
}
static void zap_completion_queue(void)
{
unsigned long flags;
struct softnet_data *sd = &get_cpu_var(softnet_data);
if (sd->completion_queue) {
struct sk_buff *clist;
local_irq_save(flags);
clist = sd->completion_queue;
sd->completion_queue = NULL;
local_irq_restore(flags);
while (clist != NULL) {
struct sk_buff *skb = clist;
clist = clist->next;
if(skb->destructor)
dev_kfree_skb_any(skb); /* put this one back */
else
__kfree_skb(skb);
}
}
put_cpu_var(softnet_data);
}
static struct sk_buff * find_skb(struct netpoll *np, int len, int reserve)
{
int once = 1, count = 0;
unsigned long flags;
struct sk_buff *skb = NULL;
zap_completion_queue();
repeat:
if (nr_skbs < MAX_SKBS)
refill_skbs();
skb = alloc_skb(len, GFP_ATOMIC);
if (!skb) {
spin_lock_irqsave(&skb_list_lock, flags);
skb = skbs;
if (skb) {
skbs = skb->next;
skb->next = NULL;
nr_skbs--;
}
spin_unlock_irqrestore(&skb_list_lock, flags);
}
if(!skb) {
count++;
if (once && (count == 1000000)) {
printk("out of netpoll skbs!\n");
once = 0;
}
netpoll_poll(np);
goto repeat;
}
atomic_set(&skb->users, 1);
skb_reserve(skb, reserve);
return skb;
}
static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
{
int status;
repeat:
if(!np || !np->dev || !netif_running(np->dev)) {
__kfree_skb(skb);
return;
}
/* avoid recursion */
if(np->poll_owner == smp_processor_id() ||
np->dev->xmit_lock_owner == smp_processor_id()) {
if (np->drop)
np->drop(skb);
else
__kfree_skb(skb);
return;
}
spin_lock(&np->dev->xmit_lock);
np->dev->xmit_lock_owner = smp_processor_id();
/*
* network drivers do not expect to be called if the queue is
* stopped.
*/
if (netif_queue_stopped(np->dev)) {
np->dev->xmit_lock_owner = -1;
spin_unlock(&np->dev->xmit_lock);
netpoll_poll(np);
goto repeat;
}
status = np->dev->hard_start_xmit(skb, np->dev);
np->dev->xmit_lock_owner = -1;
spin_unlock(&np->dev->xmit_lock);
/* transmit busy */
if(status) {
netpoll_poll(np);
goto repeat;
}
}
void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
{
int total_len, eth_len, ip_len, udp_len;
struct sk_buff *skb;
struct udphdr *udph;
struct iphdr *iph;
struct ethhdr *eth;
udp_len = len + sizeof(*udph);
ip_len = eth_len = udp_len + sizeof(*iph);
total_len = eth_len + ETH_HLEN + NET_IP_ALIGN;
skb = find_skb(np, total_len, total_len - len);
if (!skb)
return;
memcpy(skb->data, msg, len);
skb->len += len;
udph = (struct udphdr *) skb_push(skb, sizeof(*udph));
udph->source = htons(np->local_port);
udph->dest = htons(np->remote_port);
udph->len = htons(udp_len);
udph->check = 0;
iph = (struct iphdr *)skb_push(skb, sizeof(*iph));
/* iph->version = 4; iph->ihl = 5; */
put_unaligned(0x45, (unsigned char *)iph);
iph->tos = 0;
put_unaligned(htons(ip_len), &(iph->tot_len));
iph->id = 0;
iph->frag_off = 0;
iph->ttl = 64;
iph->protocol = IPPROTO_UDP;
iph->check = 0;
put_unaligned(htonl(np->local_ip), &(iph->saddr));
put_unaligned(htonl(np->remote_ip), &(iph->daddr));
iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
eth = (struct ethhdr *) skb_push(skb, ETH_HLEN);
eth->h_proto = htons(ETH_P_IP);
memcpy(eth->h_source, np->local_mac, 6);
memcpy(eth->h_dest, np->remote_mac, 6);
skb->dev = np->dev;
netpoll_send_skb(np, skb);
}
static void arp_reply(struct sk_buff *skb)
{
struct arphdr *arp;
unsigned char *arp_ptr;
int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
u32 sip, tip;
struct sk_buff *send_skb;
struct netpoll *np = skb->dev->np;
if (!np) return;
/* No arp on this interface */
if (skb->dev->flags & IFF_NOARP)
return;
if (!pskb_may_pull(skb, (sizeof(struct arphdr) +
(2 * skb->dev->addr_len) +
(2 * sizeof(u32)))))
return;
skb->h.raw = skb->nh.raw = skb->data;
arp = skb->nh.arph;
if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
arp->ar_pro != htons(ETH_P_IP) ||
arp->ar_op != htons(ARPOP_REQUEST))
return;
arp_ptr = (unsigned char *)(arp+1) + skb->dev->addr_len;
memcpy(&sip, arp_ptr, 4);
arp_ptr += 4 + skb->dev->addr_len;
memcpy(&tip, arp_ptr, 4);
/* Should we ignore arp? */
if (tip != htonl(np->local_ip) || LOOPBACK(tip) || MULTICAST(tip))
return;
size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4);
send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev),
LL_RESERVED_SPACE(np->dev));
if (!send_skb)
return;
send_skb->nh.raw = send_skb->data;
arp = (struct arphdr *) skb_put(send_skb, size);
send_skb->dev = skb->dev;
send_skb->protocol = htons(ETH_P_ARP);
/* Fill the device header for the ARP frame */
if (np->dev->hard_header &&
np->dev->hard_header(send_skb, skb->dev, ptype,
np->remote_mac, np->local_mac,
send_skb->len) < 0) {
kfree_skb(send_skb);
return;
}
/*
* Fill out the arp protocol part.
*
* we only support ethernet device type,
* which (according to RFC 1390) should always equal 1 (Ethernet).
*/
arp->ar_hrd = htons(np->dev->type);
arp->ar_pro = htons(ETH_P_IP);
arp->ar_hln = np->dev->addr_len;
arp->ar_pln = 4;
arp->ar_op = htons(type);
arp_ptr=(unsigned char *)(arp + 1);
memcpy(arp_ptr, np->dev->dev_addr, np->dev->addr_len);
arp_ptr += np->dev->addr_len;
memcpy(arp_ptr, &tip, 4);
arp_ptr += 4;
memcpy(arp_ptr, np->remote_mac, np->dev->addr_len);
arp_ptr += np->dev->addr_len;
memcpy(arp_ptr, &sip, 4);
netpoll_send_skb(np, send_skb);
}
int __netpoll_rx(struct sk_buff *skb)
{
int proto, len, ulen;
struct iphdr *iph;
struct udphdr *uh;
struct netpoll *np = skb->dev->np;
if (!np->rx_hook)
goto out;
if (skb->dev->type != ARPHRD_ETHER)
goto out;
/* check if netpoll clients need ARP */
if (skb->protocol == __constant_htons(ETH_P_ARP) &&
atomic_read(&trapped)) {
arp_reply(skb);
return 1;
}
proto = ntohs(eth_hdr(skb)->h_proto);
if (proto != ETH_P_IP)
goto out;
if (skb->pkt_type == PACKET_OTHERHOST)
goto out;
if (skb_shared(skb))
goto out;
iph = (struct iphdr *)skb->data;
if (!pskb_may_pull(skb, sizeof(struct iphdr)))
goto out;
if (iph->ihl < 5 || iph->version != 4)
goto out;
if (!pskb_may_pull(skb, iph->ihl*4))
goto out;
if (ip_fast_csum((u8 *)iph, iph->ihl) != 0)
goto out;
len = ntohs(iph->tot_len);
if (skb->len < len || len < iph->ihl*4)
goto out;
if (iph->protocol != IPPROTO_UDP)
goto out;
len -= iph->ihl*4;
uh = (struct udphdr *)(((char *)iph) + iph->ihl*4);
ulen = ntohs(uh->len);
if (ulen != len)
goto out;
if (checksum_udp(skb, uh, ulen, iph->saddr, iph->daddr) < 0)
goto out;
if (np->local_ip && np->local_ip != ntohl(iph->daddr))
goto out;
if (np->remote_ip && np->remote_ip != ntohl(iph->saddr))
goto out;
if (np->local_port && np->local_port != ntohs(uh->dest))
goto out;
np->rx_hook(np, ntohs(uh->source),
(char *)(uh+1),
ulen - sizeof(struct udphdr));
kfree_skb(skb);
return 1;
out:
if (atomic_read(&trapped)) {
kfree_skb(skb);
return 1;
}
return 0;
}
int netpoll_parse_options(struct netpoll *np, char *opt)
{
char *cur=opt, *delim;
if(*cur != '@') {
if ((delim = strchr(cur, '@')) == NULL)
goto parse_failed;
*delim=0;
np->local_port=simple_strtol(cur, NULL, 10);
cur=delim;
}
cur++;
printk(KERN_INFO "%s: local port %d\n", np->name, np->local_port);
if(*cur != '/') {
if ((delim = strchr(cur, '/')) == NULL)
goto parse_failed;
*delim=0;
np->local_ip=ntohl(in_aton(cur));
cur=delim;
printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
np->name, HIPQUAD(np->local_ip));
}
cur++;
if ( *cur != ',') {
/* parse out dev name */
if ((delim = strchr(cur, ',')) == NULL)
goto parse_failed;
*delim=0;
strlcpy(np->dev_name, cur, sizeof(np->dev_name));
cur=delim;
}
cur++;
printk(KERN_INFO "%s: interface %s\n", np->name, np->dev_name);
if ( *cur != '@' ) {
/* dst port */
if ((delim = strchr(cur, '@')) == NULL)
goto parse_failed;
*delim=0;
np->remote_port=simple_strtol(cur, NULL, 10);
cur=delim;
}
cur++;
printk(KERN_INFO "%s: remote port %d\n", np->name, np->remote_port);
/* dst ip */
if ((delim = strchr(cur, '/')) == NULL)
goto parse_failed;
*delim=0;
np->remote_ip=ntohl(in_aton(cur));
cur=delim+1;
printk(KERN_INFO "%s: remote IP %d.%d.%d.%d\n",
np->name, HIPQUAD(np->remote_ip));
if( *cur != 0 )
{
/* MAC address */
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim=0;
np->remote_mac[0]=simple_strtol(cur, NULL, 16);
cur=delim+1;
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim=0;
np->remote_mac[1]=simple_strtol(cur, NULL, 16);
cur=delim+1;
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim=0;
np->remote_mac[2]=simple_strtol(cur, NULL, 16);
cur=delim+1;
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim=0;
np->remote_mac[3]=simple_strtol(cur, NULL, 16);
cur=delim+1;
if ((delim = strchr(cur, ':')) == NULL)
goto parse_failed;
*delim=0;
np->remote_mac[4]=simple_strtol(cur, NULL, 16);
cur=delim+1;
np->remote_mac[5]=simple_strtol(cur, NULL, 16);
}
printk(KERN_INFO "%s: remote ethernet address "
"%02x:%02x:%02x:%02x:%02x:%02x\n",
np->name,
np->remote_mac[0],
np->remote_mac[1],
np->remote_mac[2],
np->remote_mac[3],
np->remote_mac[4],
np->remote_mac[5]);
return 0;
parse_failed:
printk(KERN_INFO "%s: couldn't parse config at %s!\n",
np->name, cur);
return -1;
}
int netpoll_setup(struct netpoll *np)
{
struct net_device *ndev = NULL;
struct in_device *in_dev;
np->poll_lock = SPIN_LOCK_UNLOCKED;
np->poll_owner = -1;
if (np->dev_name)
ndev = dev_get_by_name(np->dev_name);
if (!ndev) {
printk(KERN_ERR "%s: %s doesn't exist, aborting.\n",
np->name, np->dev_name);
return -1;
}
np->dev = ndev;
ndev->np = np;
if (!ndev->poll_controller) {
printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
np->name, np->dev_name);
goto release;
}
if (!netif_running(ndev)) {
unsigned long atmost, atleast;
printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
np->name, np->dev_name);
rtnl_shlock();
if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
printk(KERN_ERR "%s: failed to open %s\n",
np->name, np->dev_name);
rtnl_shunlock();
goto release;
}
rtnl_shunlock();
atleast = jiffies + HZ/10;
atmost = jiffies + 4*HZ;
while (!netif_carrier_ok(ndev)) {
if (time_after(jiffies, atmost)) {
printk(KERN_NOTICE
"%s: timeout waiting for carrier\n",
np->name);
break;
}
cond_resched();
}
/* If carrier appears to come up instantly, we don't
* trust it and pause so that we don't pump all our
* queued console messages into the bitbucket.
*/
if (time_before(jiffies, atleast)) {
printk(KERN_NOTICE "%s: carrier detect appears"
" untrustworthy, waiting 4 seconds\n",
np->name);
msleep(4000);
}
}
if (!memcmp(np->local_mac, "\0\0\0\0\0\0", 6) && ndev->dev_addr)
memcpy(np->local_mac, ndev->dev_addr, 6);
if (!np->local_ip) {
rcu_read_lock();
in_dev = __in_dev_get(ndev);
if (!in_dev || !in_dev->ifa_list) {
rcu_read_unlock();
printk(KERN_ERR "%s: no IP address for %s, aborting\n",
np->name, np->dev_name);
goto release;
}
np->local_ip = ntohl(in_dev->ifa_list->ifa_local);
rcu_read_unlock();
printk(KERN_INFO "%s: local IP %d.%d.%d.%d\n",
np->name, HIPQUAD(np->local_ip));
}
if(np->rx_hook)
np->rx_flags = NETPOLL_RX_ENABLED;
return 0;
release:
ndev->np = NULL;
np->dev = NULL;
dev_put(ndev);
return -1;
}
void netpoll_cleanup(struct netpoll *np)
{
if (np->dev)
np->dev->np = NULL;
dev_put(np->dev);
np->dev = NULL;
}
int netpoll_trap(void)
{
return atomic_read(&trapped);
}
void netpoll_set_trap(int trap)
{
if (trap)
atomic_inc(&trapped);
else
atomic_dec(&trapped);
}
EXPORT_SYMBOL(netpoll_set_trap);
EXPORT_SYMBOL(netpoll_trap);
EXPORT_SYMBOL(netpoll_parse_options);
EXPORT_SYMBOL(netpoll_setup);
EXPORT_SYMBOL(netpoll_cleanup);
EXPORT_SYMBOL(netpoll_send_udp);
EXPORT_SYMBOL(netpoll_poll);
EXPORT_SYMBOL(netpoll_queue);