linux/net/core/netpoll.c
Stephen Hemminger b6cd27ed33 netpoll per device txq
When the netpoll beast got really busy, it tended to clog
things, so it stored them for later. But the beast was putting
all it's skb's in one basket. This was bad because maybe some
pipes were clogged and others were not.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
2006-12-02 21:22:33 -08:00

795 lines
18 KiB
C

/*
* 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/if_arp.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)
#define MAX_RETRIES 20000
static struct sk_buff_head skb_pool;
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 arp_reply(struct sk_buff *skb);
static void queue_process(void *p)
{
struct netpoll_info *npinfo = p;
struct sk_buff *skb;
while ((skb = skb_dequeue(&npinfo->txq)))
dev_queue_xmit(skb);
}
void netpoll_queue(struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
struct netpoll_info *npinfo = dev->npinfo;
if (!npinfo)
kfree_skb(skb);
else {
skb_queue_tail(&npinfo->txq, skb);
schedule_work(&npinfo->tx_work);
}
}
static int checksum_udp(struct sk_buff *skb, struct udphdr *uh,
unsigned short ulen, u32 saddr, u32 daddr)
{
unsigned int psum;
if (uh->check == 0 || skb->ip_summed == CHECKSUM_UNNECESSARY)
return 0;
psum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
if (skb->ip_summed == CHECKSUM_COMPLETE &&
!(u16)csum_fold(csum_add(psum, skb->csum)))
return 0;
skb->csum = psum;
return __skb_checksum_complete(skb);
}
/*
* 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)
{
struct netpoll_info *npinfo = np->dev->npinfo;
int budget = 16;
if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
npinfo->poll_owner != smp_processor_id() &&
spin_trylock(&npinfo->poll_lock)) {
npinfo->rx_flags |= NETPOLL_RX_DROP;
atomic_inc(&trapped);
np->dev->poll(np->dev, &budget);
atomic_dec(&trapped);
npinfo->rx_flags &= ~NETPOLL_RX_DROP;
spin_unlock(&npinfo->poll_lock);
}
}
static void service_arp_queue(struct netpoll_info *npi)
{
struct sk_buff *skb;
if (unlikely(!npi))
return;
skb = skb_dequeue(&npi->arp_tx);
while (skb != NULL) {
arp_reply(skb);
skb = skb_dequeue(&npi->arp_tx);
}
return;
}
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);
service_arp_queue(np->dev->npinfo);
zap_completion_queue();
}
static void refill_skbs(void)
{
struct sk_buff *skb;
unsigned long flags;
spin_lock_irqsave(&skb_pool.lock, flags);
while (skb_pool.qlen < MAX_SKBS) {
skb = alloc_skb(MAX_SKB_SIZE, GFP_ATOMIC);
if (!skb)
break;
__skb_queue_tail(&skb_pool, skb);
}
spin_unlock_irqrestore(&skb_pool.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 count = 0;
struct sk_buff *skb;
zap_completion_queue();
refill_skbs();
repeat:
skb = alloc_skb(len, GFP_ATOMIC);
if (!skb)
skb = skb_dequeue(&skb_pool);
if(!skb) {
if (++count < 10) {
netpoll_poll(np);
goto repeat;
}
return NULL;
}
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;
struct netpoll_info *npinfo;
if (!np || !np->dev || !netif_running(np->dev)) {
__kfree_skb(skb);
return;
}
npinfo = np->dev->npinfo;
/* avoid recursion */
if (npinfo->poll_owner == smp_processor_id() ||
np->dev->xmit_lock_owner == smp_processor_id()) {
if (np->drop)
np->drop(skb);
else
__kfree_skb(skb);
return;
}
do {
npinfo->tries--;
netif_tx_lock(np->dev);
/*
* network drivers do not expect to be called if the queue is
* stopped.
*/
status = NETDEV_TX_BUSY;
if (!netif_queue_stopped(np->dev))
status = np->dev->hard_start_xmit(skb, np->dev);
netif_tx_unlock(np->dev);
/* success */
if(!status) {
npinfo->tries = MAX_RETRIES; /* reset */
return;
}
/* transmit busy */
netpoll_poll(np);
udelay(50);
} while (npinfo->tries > 0);
}
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;
skb->h.uh = 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;
udph->check = csum_tcpudp_magic(htonl(np->local_ip),
htonl(np->remote_ip),
udp_len, IPPROTO_UDP,
csum_partial((unsigned char *)udph, udp_len, 0));
if (udph->check == 0)
udph->check = -1;
skb->nh.iph = 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);
skb->mac.raw = skb->data;
skb->protocol = 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 netpoll_info *npinfo = skb->dev->npinfo;
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 = NULL;
if (npinfo->rx_np && npinfo->rx_np->dev == skb->dev)
np = npinfo->rx_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_info *npi = skb->dev->npinfo;
struct netpoll *np = npi->rx_np;
if (!np)
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)) {
skb_queue_tail(&npi->arp_tx, 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))
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;
struct netpoll_info *npinfo;
unsigned long flags;
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;
if (!ndev->npinfo) {
npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
if (!npinfo)
goto release;
npinfo->rx_flags = 0;
npinfo->rx_np = NULL;
spin_lock_init(&npinfo->poll_lock);
npinfo->poll_owner = -1;
npinfo->tries = MAX_RETRIES;
spin_lock_init(&npinfo->rx_lock);
skb_queue_head_init(&npinfo->arp_tx);
skb_queue_head_init(&npinfo->txq);
INIT_WORK(&npinfo->tx_work, queue_process, npinfo);
atomic_set(&npinfo->refcnt, 1);
} else {
npinfo = ndev->npinfo;
atomic_inc(&npinfo->refcnt);
}
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_lock();
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_unlock();
goto release;
}
rtnl_unlock();
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 (is_zero_ether_addr(np->local_mac) && ndev->dev_addr)
memcpy(np->local_mac, ndev->dev_addr, 6);
if (!np->local_ip) {
rcu_read_lock();
in_dev = __in_dev_get_rcu(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) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
npinfo->rx_flags |= NETPOLL_RX_ENABLED;
npinfo->rx_np = np;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
/* fill up the skb queue */
refill_skbs();
/* last thing to do is link it to the net device structure */
ndev->npinfo = npinfo;
/* avoid racing with NAPI reading npinfo */
synchronize_rcu();
return 0;
release:
if (!ndev->npinfo)
kfree(npinfo);
np->dev = NULL;
dev_put(ndev);
return -1;
}
static int __init netpoll_init(void) {
skb_queue_head_init(&skb_pool);
return 0;
}
core_initcall(netpoll_init);
void netpoll_cleanup(struct netpoll *np)
{
struct netpoll_info *npinfo;
unsigned long flags;
if (np->dev) {
npinfo = np->dev->npinfo;
if (npinfo) {
if (npinfo->rx_np == np) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
npinfo->rx_np = NULL;
npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
np->dev->npinfo = NULL;
if (atomic_dec_and_test(&npinfo->refcnt)) {
skb_queue_purge(&npinfo->arp_tx);
skb_queue_purge(&npinfo->txq);
flush_scheduled_work();
kfree(npinfo);
}
}
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);