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Date: Fri, 29 Aug 2008 11:58:21 +0200
From: Miklos Szeredi <mszeredi@...e.cz>
To: Eugene Teo <eugeneteo@...nel.sg>
Cc: netdev@...r.kernel.org,
linux-kernel <linux-kernel@...r.kernel.org>,
Alexandre LISSY <alexandre.lissy@...rtjog.com>
Subject: Re: Linux Kernel Splice Race Condition with page invalidation
I forgot the example programs from the forward, thanks Eugene for the
reminder.
So here they are:
epoll+splice.c
============================================================
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <sys/types.h>
#define MAX_EVENTS 32
/* #define BUF_SIZE 1400 // ==> ~ 25-30% de CPU à 4096 clients */
/* #define BUF_SIZE 32768 // ==> ~ 50% de CPU à 4096 clients */
/* #define BUF_SIZE 8192 // ==> ~ 35% de CPU à 4096 clients */
#define BUF_SIZE 131072
#define MAX_CONNEXIONS 16384
#define SERVER_IP "127.0.0.1"
#define SERVER_PORT 8003
typedef enum {
INITIAL = 1,
RECU_REQUETE_CLIENT = 2,
ATT_REPONSE_SERVEUR = 3
} proxy_status ;
struct proxy
{
unsigned char type;
int client_fd; /* fd connected to client */
int server_fd; /* fd connected to server */
/*
* 0 : client
* 1 : server
*/
ssize_t datalen;
int curpos;
proxy_status Statut;
char * buf;
struct epoll_event * ev;
struct proxy * peer;
int * tube;
};
struct poll {
void * socks_lock;
/* void * socks; */
int socket_fd;
int epoll_fd;
struct proxy * pr;
};
/* typedef struct proxy epoll_data_t; */
struct poll gpoll;
/* struct proxy Connexions[MAX_CONNEXIONS];
unsigned int curConnexionsPos = 0; */
void setnonblocking(int fd)
{
fcntl(fd, F_SETFL, ( fcntl(fd, F_GETFL) | O_NONBLOCK ));
}
/*
* Init control.
* Init epoll.
* Bind and listen on control port.
*/
void poll_init_tcp()
{
struct sockaddr_in saddr;
struct epoll_event *event;
struct proxy *Proxy;
int i = 1;
/* pthread_mutex_init(&gpoll.socks_lock, NULL);
gpoll.socks = NULL; */
/* Init epoll */
gpoll.epoll_fd = epoll_create(32);
gpoll.socket_fd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
event = (struct epoll_event *)malloc(sizeof(struct epoll_event));
Proxy = (struct proxy *)malloc(sizeof(struct proxy));
if(event == NULL || Proxy == NULL)
{
perror("malloc()");
return;
}
memset(event, 0, sizeof(struct epoll_event));
memset(Proxy, 0, sizeof(struct proxy));
event->events = EPOLLIN | EPOLLOUT;
Proxy->client_fd = gpoll.socket_fd;
Proxy->server_fd = gpoll.socket_fd;
Proxy->curpos = 0;
Proxy->ev = event;
event->data.ptr = Proxy;
gpoll.pr = Proxy;
fprintf(stderr, "Stored fd : %d, %d in %p\n", Proxy->client_fd, Proxy->server_fd, Proxy);
saddr.sin_family = AF_INET;
saddr.sin_addr.s_addr = INADDR_ANY;
saddr.sin_port = htons(8080);
if (gpoll.socket_fd == -1)
fprintf(stderr, "back-ch: socket SOCK_STREAM: %s\n", strerror(errno));
if (-1 == setsockopt(gpoll.socket_fd, SOL_SOCKET, SO_REUSEADDR, &i, sizeof (i)))
fprintf(stderr, "back-ch: setsockopt SO_REUSEADDR: %s\n", strerror(errno));
if (-1 == bind(gpoll.socket_fd, (struct sockaddr *)&saddr, sizeof (saddr)))
fprintf(stderr, "back-ch: bind: %s\n", strerror(errno));
if (-1 == listen(gpoll.socket_fd, 10))
fprintf(stderr, "ctlchannel: listen: %s\n", strerror(errno));
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_ADD, gpoll.socket_fd, event) < 0)
fprintf(stderr, "cannot control epoll");
setnonblocking(gpoll.epoll_fd);
}
/*
* This function accept an incoming connection, add it to epoll, set it to non-blocking mode,
* create a new sock struct, fill it and add it to the internal chained list.
*/
void accept_sock(void)
{
int sd, dest;
int * tube;
struct sockaddr saddr;
struct sockaddr_in dest_addr;
struct proxy * Client, * Serveur;
char * buffer;
struct epoll_event * evClient, * evServeur;
socklen_t saddrlen;
socklen_t dest_addrlen;
/* Accept connection */
saddrlen = sizeof(saddr);
sd = accept(gpoll.socket_fd, &saddr, &saddrlen);
dest_addrlen = sizeof(dest_addr);
dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(SERVER_PORT);
inet_aton(SERVER_IP, &dest_addr.sin_addr);
dest = socket(PF_INET, SOCK_STREAM, 0);
if(dest == -1)
{
perror("socket()");
return;
}
if( connect(dest, (struct sockaddr *) &dest_addr, dest_addrlen) == -1 )
{
perror("connect()");
if(shutdown(sd, SHUT_RDWR) == -1)
{
perror("shutdown()");
}
return;
}
tube = (int *)malloc(sizeof(int)*2);
Client = (struct proxy *)malloc(sizeof(struct proxy));
Serveur = (struct proxy *)malloc(sizeof(struct proxy));
evClient = (struct epoll_event *)malloc(sizeof(struct epoll_event));
evServeur = (struct epoll_event *)malloc(sizeof(struct epoll_event));
buffer = (char *)malloc(sizeof(char)*BUF_SIZE);
if(buffer == NULL || tube == NULL || Client == NULL || Serveur == NULL || evClient == NULL || evServeur == NULL)
{
perror("malloc()");
exit(EXIT_FAILURE);
}
if(pipe(tube) < 0)
{
perror("pipe()");
exit(EXIT_FAILURE);
}
Client->client_fd = sd;
Client->server_fd = dest;
Client->curpos = 0;
Client->datalen = 16;
Client->type = 0;
Client->buf = buffer;
Client->Statut = 0;
Client->ev = evClient;
Client->peer = Serveur;
Client->tube = tube;
Serveur->client_fd = sd;
Serveur->server_fd = dest;
Serveur->curpos = 0;
Serveur->datalen = 16;
Serveur->type = 1;
Serveur->buf = buffer;
Serveur->Statut = 0;
Serveur->ev = evServeur;
Serveur->peer = Client;
Serveur->tube = tube;
memset(evClient, 0, sizeof(struct epoll_event));
memset(evServeur, 0, sizeof(struct epoll_event));
evClient->events = EPOLLIN | EPOLLOUT | EPOLLET;
evClient->data.ptr = Client;
evServeur->events = EPOLLIN | EPOLLOUT | EPOLLET;
evServeur->data.ptr = Serveur;
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_ADD, sd, evClient))
fprintf(stderr, "problem with client socket");
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_ADD, dest, evServeur))
fprintf(stderr, "problem with server socket");
setnonblocking(dest);
setnonblocking(sd);
#ifdef VERBOSE
fprintf(stderr, "accept() on fd %d\n", sd);
fprintf(stderr, "connect() on fd %d\n", dest);
#endif
}
void close_socket(struct proxy * p, unsigned char peer)
{
int cfd, sfd, result;
cfd = p->client_fd;
sfd = p->server_fd;
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_DEL, cfd, NULL))
perror("epoll_ctl()");
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_DEL, sfd, NULL))
perror("epoll_ctl()");
if(p->type == 0)
{
#ifdef VERBOSE
fprintf(stderr, "Freeing buffer @ %p\n", p->buf);
#endif
free(p->buf);
#ifdef VERBOSE
fprintf(stderr, "Freeing pipe @ %p\n", p->tube);
#endif
close(p->tube[0]);
close(p->tube[1]);
free(p->tube);
}
#ifdef VERBOSE
fprintf(stderr, "Freeing struct epoll_event @ %p\n", p->ev);
#endif
free(p->ev);
if(peer == 1)
{
#ifdef VERBOSE
fprintf(stderr, "Freeing peer's struct proxy @ %p\n", p->peer);
#endif
close_socket(p->peer, 0);
}
#ifdef VERBOSE
fprintf(stderr, "Freeing struct proxy @ %p\n", p);
#endif
free(p);
#ifdef VERBOSE
fprintf(stderr, "Shutting down fds (%d, %d)\n", sfd, cfd);
#endif
result = shutdown(sfd, SHUT_RDWR);
if(result == -1)
perror("shutdown()");
result = shutdown(cfd, SHUT_RDWR);
if(result == -1)
perror("shutdown()");
}
void poll_loop()
{
struct epoll_event events[MAX_EVENTS];
int n = 0, repfd = 0, fd = 0;
long read_incoming, write_incoming, write_outcoming;
struct proxy * p;
unsigned char type;
memset(events, 0, sizeof(struct epoll_event)*MAX_EVENTS);
for(;;)
{
int nfds = epoll_wait(gpoll.epoll_fd, events, MAX_EVENTS, -1);
for (n = 0; n < nfds; ++n)
{
#ifdef DEBUG
fprintf(stderr, "(EPOLLIN=%d, EPOLLOUT=%d, EPOLLRDHUP=%d, EPOLLPRI=%d, EPOLLERR=%d, EPOLLHUP=%d)\n",
events[n].events & EPOLLIN,
events[n].events & EPOLLOUT,
events[n].events & EPOLLRDHUP,
events[n].events & EPOLLPRI,
events[n].events & EPOLLERR,
events[n].events & EPOLLHUP
);
fprintf(stderr, "Retrieving user data from %p\n", events[n].data.ptr);
#endif
p = events[n].data.ptr;
if (events[n].events & EPOLLIN)
{
if (p->server_fd == gpoll.socket_fd && (int)p->client_fd == gpoll.socket_fd)
accept_sock();
}
type = p->type;
/**
* Type :
* 0 => Client
* 1 => Serveur
**/
switch(type)
{
case 0: fd = p->client_fd;
repfd = p->server_fd;
break;
case 1: fd = p->server_fd;
repfd = p->client_fd;
break;
}
if (events[n].events & EPOLLHUP || events[n].events & EPOLLRDHUP)
{
/* Suppression des FDs concernant les sockets morts pour epoll. */
close_socket(p, 1);
continue;
}
if (events[n].events & EPOLLIN)
{
#ifdef DEBUG
fprintf(stderr, "fd %d is ready for reading !\n", fd);
#endif
if(p->buf != NULL)
{
read_incoming = splice(fd, NULL, p->tube[1], NULL, 1400, SPLICE_F_NONBLOCK | SPLICE_F_MORE | SPLICE_F_MOVE);
if(read_incoming < 0)
{
if(errno == EAGAIN)
{
fprintf(stderr, "EAGAIN: IN=%d, OUT=%d\n", fd, p->tube[1]);
continue;
}
perror("splice()");
#ifdef DEBUG
fprintf(stderr, "Was: %ld = splice(%d, %p, %d, %p, %d, %d);\n",
read_incoming,
fd,
NULL,
p->tube[1],
NULL,
12*1024,
SPLICE_F_NONBLOCK
);
#endif
break;
} else {
if(read_incoming == 0)
{
fprintf(stderr, "Something's wrong. Closing this proxy.\n");
close_socket(p, 1);
continue;
}
#ifdef DEBUG
fprintf(stderr, "Splice()'d %lu bytes from %d to %d\n", read_incoming, fd, p->tube[1]);
#endif
write_outcoming = read_incoming;
while(write_outcoming > 0)
{
write_incoming = splice(p->tube[0], NULL, repfd, NULL, write_outcoming, SPLICE_F_NONBLOCK | SPLICE_F_MORE | SPLICE_F_MOVE);
if(write_incoming < 0)
{
if(write_incoming == -EAGAIN)
{
fprintf(stderr, "EAGAIN: IN=%d, OUT=%d\n", p->tube[0], repfd);
continue;
}
perror("splice()");
break;
}
write_outcoming -= write_incoming;
#ifdef DEBUG
fprintf(stderr, "Splice()'d %lu bytes from %d to %d\n", write_incoming, p->tube[0], repfd);
#endif
#ifdef DEBUG
fprintf(stderr, "Splice()'d %lu bytes from %d to %d (via %d, %d). Still %lu bytes to send.\n", write_incoming, fd, repfd, p->tube[0], p->tube[1], write_outcoming);
#endif
}
switch(type)
{
case 0: /* Socket client prêt en lecture */
break;
case 1: /* Socket serveur prêt en lecture */
break;
}
}
}
}
}
}
}
void handler(int signo)
{
if(signo == SIGTERM || signo == SIGINT)
{
fprintf(stderr, "Got SIGTERM or SIGINT, cleaning up things ...\n");
epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_DEL, gpoll.socket_fd, NULL);
shutdown(gpoll.socket_fd, SHUT_RDWR);
free(gpoll.pr->buf);
free(gpoll.pr->ev);
free(gpoll.pr);
exit(EXIT_SUCCESS);
} else {
fprintf(stderr, "UNKNOWN SIGNAL !!! : %d\n", signo);
}
}
int main(int argc, char ** argv)
{
signal(SIGTERM, handler);
signal(SIGINT, handler);
poll_init_tcp();
poll_loop();
return EXIT_SUCCESS;
}
============================================================
epoll.c
============================================================
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <sys/types.h>
#define MAX_EVENTS 2
/* #define BUF_SIZE 1400 // ==> ~ 25-30% de CPU à 4096 clients */
/* #define BUF_SIZE 32768 // ==> ~ 50% de CPU à 4096 clients */
#define BUF_SIZE 1400 // ==> ~ 35% de CPU à 4096 clients
#define MAX_CONNEXIONS 16384
#define SERVER_IP "127.0.0.1"
#define SERVER_PORT 8003
typedef enum {
INITIAL = 1,
RECU_REQUETE_CLIENT = 2,
ATT_REPONSE_SERVEUR = 3
} proxy_status ;
struct proxy
{
unsigned char type;
int client_fd; /* fd connected to client */
int server_fd; /* fd connected to server */
/*
* 0 : client
* 1 : server
*/
ssize_t datalen;
int curpos;
proxy_status Statut;
char * buf;
struct epoll_event * ev;
struct proxy * peer;
};
struct poll {
void * socks_lock;
/* void * socks; */
int socket_fd;
int epoll_fd;
struct proxy * pr;
};
/* typedef struct proxy epoll_data_t; */
struct poll gpoll;
/* struct proxy Connexions[MAX_CONNEXIONS];
unsigned int curConnexionsPos = 0; */
void setnonblocking(int fd)
{
fcntl(fd, F_SETFL, ( fcntl(fd, F_GETFL) | O_NONBLOCK ));
}
/**
* Recherche du FD de l'autre entité.
*
* type :
* 0 => client
* 1 => serveur
int find_peer(int fd, struct proxy ** target, unsigned char * type)
{
int i, found_fd;
struct proxy *p;
fprintf(stderr, "Looking for fd %d\n", fd);
for(i = 0; i < curConnexionsPos; i++)
{
p = &Connexions[i];
fprintf(stderr, "p->client_fd=%d\np->server_fd=%d\n\n", p->client_fd, p->server_fd);
if(p->client_fd == fd)
{
found_fd = p->server_fd;
*type = 0;
}
else if(p->server_fd == fd)
{
found_fd = p->client_fd;
*type = 1;
}
*target = p;
fprintf(stderr, "Found at p=%p\n", p);
return found_fd;
}
errno = EBADF;
return -1;
}
*/
/*
* Init control.
* Init epoll.
* Bind and listen on control port.
*/
void poll_init_tcp()
{
struct sockaddr_in saddr;
struct epoll_event *event;
struct proxy *Proxy;
int i = 1;
/* pthread_mutex_init(&gpoll.socks_lock, NULL);
gpoll.socks = NULL; */
/* Init epoll */
gpoll.epoll_fd = epoll_create(2);
gpoll.socket_fd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
event = (struct epoll_event *)malloc(sizeof(struct epoll_event));
Proxy = (struct proxy *)malloc(sizeof(struct proxy));
if(event == NULL || Proxy == NULL)
{
perror("malloc()");
return;
}
memset(event, 0, sizeof(struct epoll_event));
memset(Proxy, 0, sizeof(struct proxy));
event->events = EPOLLIN | EPOLLOUT;
Proxy->client_fd = gpoll.socket_fd;
Proxy->server_fd = gpoll.socket_fd;
Proxy->curpos = 0;
Proxy->ev = event;
event->data.ptr = Proxy;
gpoll.pr = Proxy;
fprintf(stderr, "Stored fd : %d, %d in %p\n", Proxy->client_fd, Proxy->server_fd, Proxy);
saddr.sin_family = AF_INET;
saddr.sin_addr.s_addr = INADDR_ANY;
saddr.sin_port = htons(8080);
if (gpoll.socket_fd == -1)
fprintf(stderr, "back-ch: socket SOCK_STREAM: %s\n", strerror(errno));
if (-1 == setsockopt(gpoll.socket_fd, SOL_SOCKET, SO_REUSEADDR, &i, sizeof (i)))
fprintf(stderr, "back-ch: setsockopt SO_REUSEADDR: %s\n", strerror(errno));
if (-1 == bind(gpoll.socket_fd, (struct sockaddr *)&saddr, sizeof (saddr)))
fprintf(stderr, "back-ch: bind: %s\n", strerror(errno));
if (-1 == listen(gpoll.socket_fd, 10))
fprintf(stderr, "ctlchannel: listen: %s\n", strerror(errno));
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_ADD, gpoll.socket_fd, event) < 0)
fprintf(stderr, "cannot control epoll");
setnonblocking(gpoll.epoll_fd);
}
/*
* This function accept an incoming connection, add it to epoll, set it to non-blocking mode,
* create a new sock struct, fill it and add it to the internal chained list.
*/
void accept_sock(void)
{
int sd, dest;
struct sockaddr saddr;
struct sockaddr_in dest_addr;
struct proxy * Client, * Serveur;
char * buffer;
struct epoll_event * evClient, * evServeur;
socklen_t saddrlen;
socklen_t dest_addrlen;
/* Accept connection */
saddrlen = sizeof(saddr);
sd = accept(gpoll.socket_fd, &saddr, &saddrlen);
dest_addrlen = sizeof(dest_addr);
dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(SERVER_PORT);
inet_aton(SERVER_IP, &dest_addr.sin_addr);
dest = socket(PF_INET, SOCK_STREAM, 0);
if(dest == -1)
{
perror("socket()");
return;
}
if( connect(dest, (struct sockaddr *) &dest_addr, dest_addrlen) == -1 )
{
perror("connect()");
if(shutdown(sd, SHUT_RDWR) == -1)
{
perror("shutdown()");
}
return;
}
Client = (struct proxy *)malloc(sizeof(struct proxy));
Serveur = (struct proxy *)malloc(sizeof(struct proxy));
evClient = (struct epoll_event *)malloc(sizeof(struct epoll_event));
evServeur = (struct epoll_event *)malloc(sizeof(struct epoll_event));
buffer = (char *)malloc(sizeof(char)*BUF_SIZE);
if(buffer == NULL || Client == NULL || Serveur == NULL || evClient == NULL || evServeur == NULL)
{
perror("malloc()");
exit(EXIT_FAILURE);
}
Client->client_fd = sd;
Client->server_fd = dest;
Client->curpos = 0;
Client->datalen = 16;
Client->type = 0;
Client->buf = buffer;
Client->Statut = 0;
Client->ev = evClient;
Client->peer = Serveur;
Serveur->client_fd = sd;
Serveur->server_fd = dest;
Serveur->curpos = 0;
Serveur->datalen = 16;
Serveur->type = 1;
Serveur->buf = buffer;
Serveur->Statut = 0;
Serveur->ev = evServeur;
Serveur->peer = Client;
memset(evClient, 0, sizeof(struct epoll_event));
memset(evServeur, 0, sizeof(struct epoll_event));
evClient->events = EPOLLIN | EPOLLOUT | EPOLLET;
evClient->data.ptr = Client;
evServeur->events = EPOLLIN | EPOLLOUT | EPOLLET;
evServeur->data.ptr = Serveur;
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_ADD, sd, evClient))
fprintf(stderr, "problem with client socket");
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_ADD, dest, evServeur))
fprintf(stderr, "problem with server socket");
setnonblocking(dest);
setnonblocking(sd);
#ifdef VERBOSE
fprintf(stderr, "accept() on fd %d\n", sd);
fprintf(stderr, "connect() on fd %d\n", dest);
#endif
}
void close_socket(struct proxy * p, unsigned char peer)
{
int cfd, sfd, result;
cfd = p->client_fd;
sfd = p->server_fd;
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_DEL, cfd, NULL))
perror("epoll_ctl()");
if (epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_DEL, sfd, NULL))
perror("epoll_ctl()");
if(p->type == 0)
{
#ifdef VERBOSE
fprintf(stderr, "Freeing buffer @ %p\n", p->buf);
#endif
free(p->buf);
}
#ifdef VERBOSE
fprintf(stderr, "Freeing struct epoll_event @ %p\n", p->ev);
#endif
free(p->ev);
if(peer == 1)
{
#ifdef VERBOSE
fprintf(stderr, "Freeing peer's struct proxy @ %p\n", p->peer);
#endif
close_socket(p->peer, 0);
}
#ifdef VERBOSE
fprintf(stderr, "Freeing struct proxy @ %p\n", p);
#endif
free(p);
#ifdef VERBOSE
fprintf(stderr, "Shutting down fds (%d, %d)\n", sfd, cfd);
#endif
result = shutdown(sfd, SHUT_RDWR);
if(result == -1)
perror("shutdown()");
result = shutdown(cfd, SHUT_RDWR);
if(result == -1)
perror("shutdown()");
}
void poll_loop()
{
struct epoll_event events[MAX_EVENTS];
int n = 0, repfd = 0, fd = 0;
ssize_t read_incoming, write_outcoming, copied;
struct proxy * p;
unsigned char type;
memset(events, 0, sizeof(struct epoll_event)*MAX_EVENTS);
for(;;)
{
int nfds = epoll_wait(gpoll.epoll_fd, events, MAX_EVENTS, -1);
for (n = 0; n < nfds; ++n)
{
#ifdef DEBUG
fprintf(stderr, "(EPOLLIN=%d, EPOLLOUT=%d, EPOLLRDHUP=%d, EPOLLPRI=%d, EPOLLERR=%d, EPOLLHUP=%d)\n",
events[n].events & EPOLLIN,
events[n].events & EPOLLOUT,
events[n].events & EPOLLRDHUP,
events[n].events & EPOLLPRI,
events[n].events & EPOLLERR,
events[n].events & EPOLLHUP
);
fprintf(stderr, "Retrieving user data from %p\n", events[n].data.ptr);
#endif
p = events[n].data.ptr;
if (events[n].events & EPOLLIN)
{
if (p->server_fd == gpoll.socket_fd && (int)p->client_fd == gpoll.socket_fd)
accept_sock();
}
type = p->type;
/**
* Type :
* 0 => Client
* 1 => Serveur
**/
switch(type)
{
case 0: fd = p->client_fd;
repfd = p->server_fd;
break;
case 1: fd = p->server_fd;
repfd = p->client_fd;
break;
}
if (events[n].events & EPOLLHUP)
{
/* Suppression des FDs concernant les sockets morts pour epoll. */
close_socket(p, 1);
continue;
}
if (events[n].events & EPOLLIN)
{
#ifdef DEBUG
fprintf(stderr, "fd %d is ready for reading into %p.\n", fd, p->buf);
#endif
if(p->buf != NULL)
{
read_incoming = read(fd, p->buf, BUF_SIZE);
p->datalen = read_incoming;
#ifdef DEBUG
fprintf(stderr, "Read %d bytes from %d.\n", read_incoming, fd);
#endif
if(read_incoming == 0)
{
fprintf(stderr, "Something's wrong on fd %d : I got no data.\n", fd);
/* close_socket(p, 1); */
continue;
}
copied = write(repfd, p->buf, p->datalen);
p->datalen -= copied;
switch(type)
{
case 0: /* Socket client prêt en lecture */
break;
case 1: /* Socket serveur prêt en lecture */
break;
}
}
}
/*
else if (events[n].events & EPOLLOUT)
{
#ifdef DEBUG
fprintf(stderr, "fd %d is ready for writing. ", fd);
#endif
if(p != NULL && p->buf != NULL && p->datalen > 0)
{
write_outcoming = write(fd, p->buf, p->datalen);
p->datalen -= write_outcoming;
#ifdef DEBUG
fprintf(stderr, "Write %d bytes to %d.\n", write_outcoming, fd);
#endif
switch(type)
{
case 0: // Socket client prêt en écriture
break;
case 1: // Socket serveur prêt en écriture
break;
}
}
}
*/
}
}
}
void handler(int signo)
{
if(signo == SIGTERM || signo == SIGINT)
{
fprintf(stderr, "Got SIGTERM or SIGINT, cleaning up things ...\n");
epoll_ctl(gpoll.epoll_fd, EPOLL_CTL_DEL, gpoll.socket_fd, NULL);
shutdown(gpoll.socket_fd, SHUT_RDWR);
free(gpoll.pr->buf);
free(gpoll.pr->ev);
free(gpoll.pr);
exit(EXIT_SUCCESS);
} else {
fprintf(stderr, "UNKNOWN SIGNAL !!! : %d\n", signo);
}
}
int main(int argc, char ** argv)
{
signal(SIGTERM, handler);
signal(SIGINT, handler);
poll_init_tcp();
poll_loop();
return EXIT_SUCCESS;
}
============================================================
On Thu, 2008-08-28 at 18:15 +0200, Miklos Szeredi wrote:
> Thanks, forwarding to mailing lists.
>
> Since you are in a better position to test (already have the
> installation and configuration set up) I'm not going to try to reproduce
> this until you tried 2.6.26.
>
> Thanks,
> Miklos
>
> On Thu, 2008-08-28 at 17:43 +0200, Alexandre LISSY wrote:
> > Le Thursday 28 August 2008 17:36:41, vous avez écrit :
> > > Hi Alexandre,
> > >
> > > On Thu, 2008-08-28 at 16:49 +0200, Alexandre LISSY wrote:
> > > > I saw your mail on LKML, and I feel like I'm experiencing the issue.
> > > > I'm using a 2.6.25-2-amd64 (from Debian), on two machines, one with 32
> > > > bits user land, and the other with 64 bits userland. I also tried with
> > > > 2.6.25-2-686.
> > >
> > > Thanks for the report. Usually it's best to send such a report not just
> > > to an individual developer, but to relevant mailing lists as well (in
> > > this case <linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>).
> > > Would you mind if I forwarded your mail to these lists?
> > No problem, I wasn't sure this was the good audience.
> >
> > >
> > > > I'm trying to achieve a really fast tcp proxy, mostly for testing
> > > > purpose. Attached is my code, so you can check, and maybe reproduce :)
> > >
> > > Thanks. I don't know how I can use these programs to reproduce the
> > > problem. Can you please describe in detail how to set up and run the
> > > test environment?
> > Just compile my code, install a icecast that provide a 128k mp3 stream.
> > Pay attention, the addresses are hardcoded in source, so you need to recompile
> > for any change.
> >
> > Then, launch many wget or any other tool capable of parallel download, to
> > stress the proxy.
> >
> > >
> > > > If I use the local icecast (the one on 127.0.0.1), then, I can reach
> > > > 62Mbits, if kernel didn't trashed in the middle of the operation (confere
> > > > "Kernel having fun"), leaving my process unkillable. Need to reboot :/.
> > >
> > > This is because of the kernel BUG that you've reported below. I found
> > > this similar report:
> > Yeah, I figured that's linked :)
> >
> > >
> > > http://article.gmane.org/gmane.linux.network/94988
> > >
> > > This may have been fixed in linux-2.6.26. Could you try a 2.6.26
> > > kernel, to see if you can still reproduce the problem?
> > I'll grab a 2.6.26 from unstable tomorrow and check if it continues to
> > happens.
> >
> > Thanks for your help :)
> >
> > >
> > > Thanks,
> > > Miklos
> > >
> > > > And while it's not trashed, I get many "splice(): Resource temporarily
> > > > unavailable", that don't come up when using a remote icecast.
> > > >
> > > > So, as the only difference is local/remote, I think that latency matters,
> > > > and considering your message about a race condition, I'm wondering ...
> > > >
> > > > Thanks for any help/hint !
> > > >
> > > > ---Kernel having fun---
> > > > [65611.886737] BUG: unable to handle kernel NULL pointer dereference at
> > > > 0000000000000008
> > > > [65611.886737] IP: [<ffffffff803db40d>] tcp_read_sock+0xec/0x1a3
> > > > [65611.886737] PGD 1fc64067 PUD 2f2a7067 PMD 0
> > > > [65611.886737] Oops: 0002 [1] SMP
> > > > [65611.886737] CPU 1
> > > > [65611.886737] Modules linked in: ipv6 bonding dm_snapshot dm_mirror
> > > > dm_mod loop iTCO_wdt ses i5000_edac pcspkr psmouse evdev dcdbas rng_core
> > > > button edac_core ixgbe shpchp pci_hotplug serio_raw enclosure ext3 jbd
> > > > mbcache raid1 md_mod ide_generic ide_cd_mod cdrom ata_generic libata dock
> > > > sd_mod piix ide_core ehci_hcd uhci_hcd megaraid_sas bnx2 firmware_class
> > > > scsi_mod thermal processor fan
> > > > [65611.886737] Pid: 18679, comm: epoll+splice+st Not tainted
> > > > 2.6.25-2-amd64 #1 [65611.886737] RIP: 0010:[<ffffffff803db40d>]
> > > > [<ffffffff803db40d>] tcp_read_sock+0xec/0x1a3
> > > > [65611.886737] RSP: 0018:ffff81006db59e68 EFLAGS: 00010202
> > > > [65611.886737] RAX: 0000000000000000 RBX: ffff810073c504a0 RCX:
> > > > 0000000000000000
> > > > [65611.886737] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> > > > ffff810073c504a0
> > > > [65611.886737] RBP: 0000000000000578 R08: ffff81006d5a2080 R09:
> > > > 0000000000000000
> > > > [65611.886737] R10: ffff810065663980 R11: ffffffff802f0637 R12:
> > > > 0000000000000578
> > > > [65611.886737] R13: ffff81006d5a2080 R14: 000000001e5b23ed R15:
> > > > ffff81006d5a2130
> > > > [65611.886737] FS: 0000000000be2850(0063) GS:ffff81007f76db40(0000)
> > > > knlGS:0000000000000000
> > > > [65611.886737] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> > > > [65611.886737] CR2: 0000000000000008 CR3: 0000000061b55000 CR4:
> > > > 00000000000006e0
> > > > [65611.886737] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> > > > 0000000000000000
> > > > [65611.886737] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
> > > > 0000000000000400
> > > > [65611.886737] Process epoll+splice+st (pid: 18679, threadinfo
> > > > ffff81006db58000, task ffff81007ee45180)
> > > > [65611.886737] Stack: ffffffff803db596 ffff81006db59eb8 000005782628a210
> > > > ffff81006d5a2080
> > > > [65611.886737] 0000000000000000 0000000000000000 0000000000000007
> > > > 0000000000000000
> > > > [65611.886737] 0000000000000578 ffffffff803dbb14 0000000000000000
> > > > 0000000000000000
> > > > [65611.886737] Call Trace:
> > > > [65611.886737] [<ffffffff803db596>] ? tcp_splice_data_recv+0x0/0x1c
> > > > [65611.886737] [<ffffffff803dbb14>] ? tcp_splice_read+0x82/0x1ce
> > > > [65611.886737] [<ffffffff802b7962>] ? sys_splice+0x1b0/0x23e
> > > > [65611.886737] [<ffffffff8020bd9a>] ? system_call_after_swapgs+0x8a/0x8f
> > > > [65611.886737]
> > > > [65611.886737]
> > > > [65611.886737] Code: 00 00 00 f6 44 10 0d 01 0f 85 67 ff ff ff 41 ff 4f
> > > > 10 48 89 df 48 8b 43 08 48 8b 13 48 c7 43 08 00 00 00 00 48 c7 03 00 00
> > > > 00 00 <48> 89 42 08 48 89 10 e8 ab 1b fd ff 48 8b 44 24 08 48 83 78 08
> > > > [65611.886737] RIP [<ffffffff803db40d>] tcp_read_sock+0xec/0x1a3
> > > > [65611.886737] RSP <ffff81006db59e68>
> > > > [65611.886737] CR2: 0000000000000008
> > > > [65611.886774] ---[ end trace 8f47273d77faf3c8 ]---
> > > > ---Kernel having fun---
> >
> >
>
--
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