php 公司网站,做竞价的网站可以做优化吗,专业网站建设必要性,如何制作统计小程序零拷贝技术介绍#xff1a;史上最全零拷贝总结-CSDN博客
这是一个简单的基于epoll的Linux TCP代理程序#xff0c;通过匿名管道和零拷贝技术的splice函数#xff0c;将两个TCP端口相互连接#xff0c;并转发数据。
#define _GNU_SOURCE 1
#include sys/socket.h
…零拷贝技术介绍史上最全零拷贝总结-CSDN博客
这是一个简单的基于epoll的Linux TCP代理程序通过匿名管道和零拷贝技术的splice函数将两个TCP端口相互连接并转发数据。
#define _GNU_SOURCE 1
#include sys/socket.h
#include sys/epoll.h
#include sys/ioctl.h
#include stdio.h
#include stdlib.h
#include limits.h
#include unistd.h
#include fcntl.h
#include netdb.h
#include stdbool.h
#include errno.h
#include assert.h
#include time.h
#include list.h#define err(x) perror(x), exit(1)
#define NEW(x) ((x) xmalloc(sizeof(*(x))))
#define MAX(a,b) ((a) (b) ? (a) : (b))int connection_timeout 5; /* XXX configurable */void oom(void)
{fprintf(stderr, Out of memory\n);exit(1);
}void *xmalloc(size_t size)
{void *p calloc(size, 1);if (!p)oom();return p;
}void *xrealloc(void *old, size_t size)
{void *p realloc(old, size);if (!p)oom();return p;
}struct addrinfo *resolve(char *name, char *port, int flags)
{int ret;struct addrinfo *adr;struct addrinfo hint { .ai_flags flags };ret getaddrinfo(name, port, hint, adr);if (ret) {fprintf(stderr, proxy: Cannot resolve %s %s: %s\n,name, port, gai_strerror(ret));exit(1);}return adr;
}void setnonblock(int fd, int *cache)
{int flags;if (!cache || *cache -1) {flags fcntl(fd, F_GETFL, 0);if (cache)*cache flags;} elseflags *cache;fcntl(fd, F_SETFL, flags|O_NONBLOCK);
}struct buffer {int pipe[2];int bytes;
};struct conn {struct conn *other;int fd;struct buffer buf;time_t expire;struct list_head expire_node;
};LIST_HEAD(expire_list);#define MIN_EVENTS 32
struct epoll_event *events;
int num_events, max_events;int epoll_add(int efd, int fd, int revents, void *conn)
{struct epoll_event ev { .events revents, .data.ptr conn };if (num_events max_events) {max_events MAX(max_events * 2, MIN_EVENTS);events xrealloc(events, sizeof(struct epoll_event) * max_events);}return epoll_ctl(efd, EPOLL_CTL_ADD, fd, ev);
}int epoll_del(int efd, int fd)
{num_events--;assert(num_events 0);return epoll_ctl(efd, EPOLL_CTL_DEL, fd, (void *)1L);
}/* Create buffer between two connections */
struct buffer *newbuffer(struct buffer *buf)
{if (pipe2(buf-pipe, O_NONBLOCK) 0) {perror(pipe);return NULL;}return buf;
}void delbuffer(struct buffer *buf)
{close(buf-pipe[0]);close(buf-pipe[1]);
}void delconn(int efd, struct conn *conn)
{list_del(conn-expire_node);delbuffer(conn-buf);epoll_del(efd, conn-fd);close(conn-fd);free(conn);
}struct conn *newconn(int efd, int fd, time_t now)
{struct conn *conn;NEW(conn);conn-fd fd;if (!newbuffer(conn-buf)) {delconn(efd, conn);return NULL;}if (epoll_add(efd, fd, EPOLLIN|EPOLLOUT|EPOLLET, conn) 0) {perror(epoll);delconn(efd, conn);return NULL;}conn-expire now connection_timeout;list_add_tail(conn-expire_node, expire_list);return conn;
}/* Process incoming connection. */
void new_request(int efd, int lfd, int *cache, time_t now)
{int newsk accept(lfd, NULL, NULL);if (newsk 0) {perror(accept);return;}// xxx logsetnonblock(newsk, cache);newconn(efd, newsk, now);
}/* Open outgoing connection */
struct conn *
openconn(int efd, struct addrinfo *host, int *cache, struct conn *other,time_t now)
{int outfd socket(host-ai_family, SOCK_STREAM, 0);if (outfd 0)return NULL;setnonblock(outfd, cache);int n connect(outfd, host-ai_addr, host-ai_addrlen);if (n 0 errno ! EINPROGRESS) {perror(connect);close(outfd);return NULL;}struct conn *conn newconn(efd, outfd, now);if (conn) {conn-other other;other-other conn;}return conn;
}#define BUFSZ 16384 /* XXX *//* Move from socket to pipe */
bool move_data_in(int srcfd, struct buffer *buf)
{for (;;) { int n splice(srcfd, NULL, buf-pipe[1], NULL, BUFSZ, SPLICE_F_NONBLOCK|SPLICE_F_MOVE);if (n 0)buf-bytes n;if (n 0)return false;if (n 0) {if (errno EAGAIN || errno EWOULDBLOCK)return true;return false;}}return true;
}/* From pipe to socket */
bool move_data_out(struct buffer *buf, int dstfd)
{ while (buf-bytes 0) {int bytes buf-bytes;if (bytes BUFSZ)bytes BUFSZ;int n splice(buf-pipe[0], NULL, dstfd, NULL,bytes, SPLICE_F_NONBLOCK|SPLICE_F_MOVE);if (n 0)break;if (n 0) {if (errno EAGAIN || errno EWOULDBLOCK)break;return false;}buf-bytes - n;}/* bytes 0, add dst to epoll set *//* else remove if it was added */return true;
}void closeconn(int efd, struct conn *conn)
{if (conn-other)delconn(efd, conn-other);delconn(efd, conn);
}int expire_connections(int efd, time_t now)
{struct conn *conn, *tmp;list_for_each_entry_safe (conn, tmp, expire_list, expire_node) {if (conn-expire now)return (conn-expire - now) * 1000;closeconn(efd, conn);}return -1;
}void touch_conn(struct conn *conn, time_t now)
{conn-expire now connection_timeout;list_del(conn-expire_node);list_add_tail(conn-expire_node, expire_list);
}int listen_socket(int efd, char *lname, char *port)
{struct addrinfo *laddr resolve(lname, port, AI_PASSIVE);int lfd socket(laddr-ai_family, SOCK_STREAM, 0);if (lfd 0) err(socket);int opt 1;if (setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, opt, sizeof(int)) 0) err(SO_REUSEADDR);if (bind(lfd, laddr-ai_addr, laddr-ai_addrlen) 0) err(bind);if (listen(lfd, 20) 0) err(listen);setnonblock(lfd, NULL);freeaddrinfo(laddr);if (epoll_add(efd, lfd, EPOLLIN, NULL) 0) err(epoll add listen fd);return lfd;
}int main(int ac, char **av)
{if (ac ! 4 ac ! 5) {fprintf(stderr,Usage: proxy inport outhost outport [listenaddr]\n);exit(1);}struct addrinfo *outhost resolve(av[2], av[3], 0);int efd epoll_create(10);if (efd 0) err(epoll_create);int lfd listen_socket(efd, av[4] ? av[4] : 0.0.0.0, av[1]);int cache_in -1, cache_out -1; int timeo -1;for (;;) {int nfds epoll_wait(efd, events, num_events, timeo);if (nfds 0) {perror(epoll);continue;}time_t now time(NULL);int i;for (i 0; i nfds; i) { struct epoll_event *ev events[i];struct conn *conn ev-data.ptr;/* listen socket */if (conn NULL) {if (ev-events EPOLLIN)new_request(efd, lfd, cache_in, now);continue;} if (ev-events (EPOLLERR|EPOLLHUP)) {closeconn(efd, conn);continue;}struct conn *other conn-other;/* No attempt for partial close right now */if (ev-events EPOLLIN) {touch_conn(conn, now);if (!other)other openconn(efd, outhost, cache_out,conn, now);bool in move_data_in(conn-fd, conn-buf);bool out move_data_out(conn-buf, other-fd);if (!in || !out) { closeconn(efd, conn);continue;}touch_conn(other, now);} if ((ev-events EPOLLOUT) other) {if (!move_data_out(other-buf, conn-fd))delconn(efd, conn);elsetouch_conn(conn, now);/* When the pipe filled up could havelost input events. Unfortunatelysplice doesnt tell us which endwas responsible for 0, so have to askexplicitely. */int len 0;if (ioctl(other-fd, FIONREAD, len) 0)perror(ioctl);if (len 0) {if (!move_data_in(other-fd, other-buf))closeconn(efd, other);}}} timeo expire_connections(efd, now);}return 0;
}
