miniupnp/miniupnpd/asyncsendto.c

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/* $Id: asyncsendto.c,v 1.12 2020/11/11 12:13:26 nanard Exp $ */
/* MiniUPnP project
* http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
* (c) 2006-2020 Thomas Bernard
* This software is subject to the conditions detailed
* in the LICENCE file provided within the distribution */
#include <sys/types.h>
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#include <sys/select.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <stdlib.h>
#include <string.h>
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#include <unistd.h>
#include <syslog.h>
#include <errno.h>
#include <sys/uio.h>
#include <netinet/in.h>
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#include <inttypes.h>
#include "asyncsendto.h"
#include "upnputils.h"
enum send_state {ESCHEDULED=1, EWAITREADY=2, ESENDNOW=3} state;
/* state diagram for a packet :
*
* |
* V
* -> ESCHEDULED -> ESENDNOW -> sent
* ^ |
* | V
* EWAITREADY -> sent
*/
struct scheduled_send {
LIST_ENTRY(scheduled_send) entries;
struct timeval ts;
enum send_state state;
int sockfd;
const void * buf;
size_t len;
int flags;
const struct sockaddr *dest_addr;
socklen_t addrlen;
const struct sockaddr_in6 *src_addr;
char data[];
};
static LIST_HEAD(listhead, scheduled_send) send_list = { NULL };
/*
* ssize_t sendto(int sockfd, const void *buf, size_t len, int flags,
* const struct sockaddr *dest_addr, socklen_t addrlen);
*/
static ssize_t
send_from_to(int sockfd, const void *buf, size_t len, int flags,
const struct sockaddr_in6 *src_addr,
const struct sockaddr *dest_addr, socklen_t addrlen)
{
#ifdef IPV6_PKTINFO
if(src_addr) {
struct iovec iov;
struct in6_pktinfo ipi6;
uint8_t c[CMSG_SPACE(sizeof(ipi6))];
struct msghdr msg;
struct cmsghdr* cmsg;
iov.iov_base = (void *)buf;
iov.iov_len = len;
memset(&msg, 0, sizeof(msg));
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
ipi6.ipi6_addr = src_addr->sin6_addr;
ipi6.ipi6_ifindex = src_addr->sin6_scope_id;
msg.msg_control = c;
msg.msg_controllen = sizeof(c);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_PKTINFO;
cmsg->cmsg_len = CMSG_LEN(sizeof(ipi6));
memcpy(CMSG_DATA(cmsg), &ipi6, sizeof(ipi6));
msg.msg_name = (void *)dest_addr;
msg.msg_namelen = addrlen;
return sendmsg(sockfd, &msg, flags);
} else {
#endif /* IPV6_PKTINFO */
return sendto(sockfd, buf, len, flags, dest_addr, addrlen);
#ifdef IPV6_PKTINFO
}
#endif /* IPV6_PKTINFO */
}
/* delay = milli seconds */
ssize_t
sendto_schedule2(int sockfd, const void *buf, size_t len, int flags,
const struct sockaddr *dest_addr, socklen_t addrlen,
const struct sockaddr_in6 *src_addr,
unsigned int delay)
{
enum send_state state;
ssize_t n;
size_t alloc_len;
struct timeval tv;
struct scheduled_send * elt;
if(delay == 0) {
/* first try to send at once */
n = send_from_to(sockfd, buf, len, flags, src_addr, dest_addr, addrlen);
if(n >= 0)
return n;
else if(errno == EAGAIN || errno == EWOULDBLOCK) {
/* use select() on this socket */
state = EWAITREADY;
} else if(errno == EINTR) {
state = ESENDNOW;
} else {
/* uncatched error */
return n;
}
} else {
state = ESCHEDULED;
}
/* schedule */
if(upnp_gettimeofday(&tv) < 0) {
return -1;
}
/* allocate enough space for structure + buffers */
alloc_len = sizeof(struct scheduled_send) + len + addrlen;
if(src_addr)
alloc_len += sizeof(struct sockaddr_in6);
elt = malloc(alloc_len);
if(elt == NULL) {
syslog(LOG_ERR, "malloc failed to allocate %u bytes",
(unsigned)alloc_len);
return -1;
}
elt->state = state;
/* time the packet should be sent */
elt->ts.tv_sec = tv.tv_sec + (delay / 1000);
elt->ts.tv_usec = tv.tv_usec + (delay % 1000) * 1000;
if(elt->ts.tv_usec > 1000000) {
elt->ts.tv_sec++;
elt->ts.tv_usec -= 1000000;
}
elt->sockfd = sockfd;
elt->flags = flags;
memcpy(elt->data, dest_addr, addrlen);
elt->dest_addr = (struct sockaddr *)elt->data;
elt->addrlen = addrlen;
if(src_addr) {
elt->src_addr = (struct sockaddr_in6 *)(elt->data + addrlen);
memcpy((void *)elt->src_addr, src_addr, sizeof(struct sockaddr_in6));
elt->buf = (void *)(elt->data + addrlen + sizeof(struct sockaddr_in6));
} else {
elt->src_addr = NULL;
elt->buf = (void *)(elt->data + addrlen);
}
elt->len = len;
memcpy((void *)elt->buf, buf, len);
/* insert */
LIST_INSERT_HEAD( &send_list, elt, entries);
return 0;
}
/* try to send at once, and queue the packet if needed */
ssize_t
sendto_or_schedule(int sockfd, const void *buf, size_t len, int flags,
const struct sockaddr *dest_addr, socklen_t addrlen)
{
return sendto_schedule2(sockfd, buf, len, flags, dest_addr, addrlen, NULL, 0);
}
ssize_t
sendto_or_schedule2(int sockfd, const void *buf, size_t len, int flags,
const struct sockaddr *dest_addr, socklen_t addrlen,
const struct sockaddr_in6 *src_addr)
{
return sendto_schedule2(sockfd, buf, len, flags, dest_addr, addrlen, src_addr, 0);
}
/* get_next_scheduled_send() return number of scheduled send in list */
int get_next_scheduled_send(struct timeval * next_send)
{
int n = 0;
struct scheduled_send * elt;
if(next_send == NULL)
return -1;
for(elt = send_list.lh_first; elt != NULL; elt = elt->entries.le_next) {
if(n == 0 || (elt->ts.tv_sec < next_send->tv_sec) ||
(elt->ts.tv_sec == next_send->tv_sec && elt->ts.tv_usec < next_send->tv_usec)) {
next_send->tv_sec = elt->ts.tv_sec;
next_send->tv_usec = elt->ts.tv_usec;
}
n++;
}
return n;
}
/* update writefds for select() call
* return the number of packets to try to send at once */
int get_sendto_fds(fd_set * writefds, int * max_fd, const struct timeval * now)
{
int n = 0;
struct scheduled_send * elt;
for(elt = send_list.lh_first; elt != NULL; elt = elt->entries.le_next) {
if(elt->state == EWAITREADY) {
/* last sendto() call returned EAGAIN/EWOULDBLOCK */
FD_SET(elt->sockfd, writefds);
if(elt->sockfd > *max_fd)
*max_fd = elt->sockfd;
n++;
} else if((elt->ts.tv_sec < now->tv_sec) ||
(elt->ts.tv_sec == now->tv_sec && elt->ts.tv_usec <= now->tv_usec)) {
/* we waited long enough, now send ! */
elt->state = ESENDNOW;
n++;
}
}
return n;
}
/* executed sendto() when needed */
int try_sendto(fd_set * writefds)
{
int ret = 0;
ssize_t n;
struct scheduled_send * elt;
struct scheduled_send * next;
for(elt = send_list.lh_first; elt != NULL; elt = next) {
next = elt->entries.le_next;
if((elt->state == ESENDNOW) ||
(elt->state == EWAITREADY && FD_ISSET(elt->sockfd, writefds))) {
#ifdef DEBUG
syslog(LOG_DEBUG, "%s: %d bytes on socket %d",
"try_sendto", (int)elt->len, elt->sockfd);
#endif
n = send_from_to(elt->sockfd, elt->buf, elt->len, elt->flags,
elt->src_addr, elt->dest_addr, elt->addrlen);
/*n = sendto(elt->sockfd, elt->buf, elt->len, elt->flags,
elt->dest_addr, elt->addrlen);*/
if(n < 0) {
if(errno == EINTR) {
/* retry at once */
elt->state = ESENDNOW;
continue;
} else if(errno == EAGAIN || errno == EWOULDBLOCK) {
/* retry once the socket is ready for writing */
elt->state = EWAITREADY;
continue;
} else {
char addr_str[64];
/* uncatched error */
if(sockaddr_to_string(elt->dest_addr, addr_str, sizeof(addr_str)) <= 0)
addr_str[0] = '\0';
syslog(LOG_ERR, "%s(sock=%d, len=%u, dest=%s): sendto: %m",
"try_sendto", elt->sockfd, (unsigned)elt->len,
addr_str);
ret--;
}
} else if((int)n != (int)elt->len) {
syslog(LOG_WARNING, "%s: %d bytes sent out of %d",
"try_sendto", (int)n, (int)elt->len);
}
/* remove from the list */
LIST_REMOVE(elt, entries);
free(elt);
}
}
return ret;
}
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/* maximum execution time for finalize_sendto() in milliseconds */
#define FINALIZE_SENDTO_DELAY (500)
/* empty the list */
void finalize_sendto(void)
{
ssize_t n;
struct scheduled_send * elt;
struct scheduled_send * next;
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fd_set writefds;
struct timeval deadline;
struct timeval now;
struct timeval timeout;
int max_fd;
if(upnp_gettimeofday(&deadline) < 0) {
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syslog(LOG_ERR, "gettimeofday: %m");
return;
}
deadline.tv_usec += FINALIZE_SENDTO_DELAY*1000;
if(deadline.tv_usec > 1000000) {
deadline.tv_sec++;
deadline.tv_usec -= 1000000;
}
while(send_list.lh_first) {
FD_ZERO(&writefds);
max_fd = -1;
for(elt = send_list.lh_first; elt != NULL; elt = next) {
next = elt->entries.le_next;
syslog(LOG_DEBUG, "finalize_sendto(): %d bytes on socket %d",
(int)elt->len, elt->sockfd);
n = send_from_to(elt->sockfd, elt->buf, elt->len, elt->flags,
elt->src_addr, elt->dest_addr, elt->addrlen);
/*n = sendto(elt->sockfd, elt->buf, elt->len, elt->flags,
elt->dest_addr, elt->addrlen);*/
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if(n < 0) {
if(errno==EAGAIN || errno==EWOULDBLOCK) {
FD_SET(elt->sockfd, &writefds);
if(elt->sockfd > max_fd)
max_fd = elt->sockfd;
continue;
}
syslog(LOG_WARNING, "finalize_sendto(): socket=%d sendto: %m", elt->sockfd);
}
/* remove from the list */
LIST_REMOVE(elt, entries);
free(elt);
}
/* check deadline */
if(upnp_gettimeofday(&now) < 0) {
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syslog(LOG_ERR, "gettimeofday: %m");
return;
}
if(now.tv_sec > deadline.tv_sec ||
(now.tv_sec == deadline.tv_sec && now.tv_usec > deadline.tv_usec)) {
/* deadline ! */
while((elt = send_list.lh_first) != NULL) {
LIST_REMOVE(elt, entries);
free(elt);
}
return;
}
/* compute timeout value */
timeout.tv_sec = deadline.tv_sec - now.tv_sec;
timeout.tv_usec = deadline.tv_usec - now.tv_usec;
if(timeout.tv_usec < 0) {
timeout.tv_sec--;
timeout.tv_usec += 1000000;
}
if(max_fd >= 0) {
if(select(max_fd + 1, NULL, &writefds, NULL, &timeout) < 0) {
syslog(LOG_ERR, "select: %m");
return;
}
}
}
}