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/*
* dgrambuf.c - C datagrams buffer.
*
* Copyright 2016 by Ludovic Pouzenc <ludovic@pouzenc.fr>
*/
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include "dgrambuf.h"
#include <sys/socket.h> /* recvmmsg() */
#include <stdlib.h> /* calloc(), free() */
#include <stdio.h> /* perror() */
#include <string.h> /* memset() */
#include <sys/uio.h> /* writev() */
struct dgrambuf_t {
size_t dgram_count;
size_t dgram_max_size;
struct iovec *recv_iovecs;
struct iovec *write_iovecs;
struct mmsghdr *msgs;
int buf_full;
size_t buf_head;
size_t buf_tail;
void *buf;
unsigned int (*validate_func)(unsigned int, void *);
//TODO pthread_mutex_lock
};
void dgrambuf_set_validate_func(dgrambuf_t dbuf, unsigned int (*func)(unsigned int, void *) ) {
dbuf->validate_func = func;
}
int dgrambuf_recvmmsg(dgrambuf_t dbuf, int sockfd) {
size_t vlen, s, i;
int recv_msg_count;
unsigned int seq;
if (dbuf->buf_full) {
return -1; //TODO block until write
}
/* Determine how many message we can read at once */
if ( dbuf->buf_head < dbuf->buf_tail ) {
vlen = dbuf->buf_tail - dbuf->buf_head - 1;
} else {
vlen = dbuf->dgram_count - dbuf->buf_head;
}
/* Initialize recvmmsg arguments */
s = dbuf->buf_head;
memset(dbuf->msgs + s, 0, vlen * sizeof(struct mmsghdr));
for (i=0; i<vlen; i++) {
dbuf->recv_iovecs[s+i].iov_base = dbuf->buf + (s+i)*dbuf->dgram_count;
dbuf->recv_iovecs[s+i].iov_len = dbuf->dgram_max_size;
dbuf->msgs[s+i].msg_hdr.msg_iov = &dbuf->recv_iovecs[s+i];
dbuf->msgs[s+i].msg_hdr.msg_iovlen = 1;
}
/* Do the syscall */
recv_msg_count = recvmmsg(sockfd, dbuf->msgs + s, vlen, MSG_WAITFORONE, NULL);
if (recv_msg_count == -1) {
perror("recvmmsg()");
} else {
/* Update structure values accordingly */
dbuf->buf_head = ( dbuf->buf_head + recv_msg_count ) % dbuf->dgram_count;
dbuf->buf_full = ( dbuf->buf_head == dbuf->buf_tail );
}
/* Check all received messages */
if ( dbuf->validate_func ) {
for (i=0; i<recv_msg_count; i++) {
seq = dbuf->validate_func(dbuf->msgs[s+i].msg_len, dbuf->recv_iovecs[s+i].iov_base);
if ( seq > 0 ) {
// TODO Valid
printf("#%i valid\n", s+i);
} else {
// TODO Invalid
printf("#%i invalid\n", s+i);
}
}
}
return recv_msg_count;
}
ssize_t dgrambuf_write(dgrambuf_t dbuf, int fd) {
int i, s, vlen;
//TODO
s = 0;
vlen = 0;
for (i=0; i<vlen; i++) {
dbuf->write_iovecs[i].iov_base = dbuf->recv_iovecs[s+i].iov_base + 10;
dbuf->write_iovecs[i].iov_len = dbuf->msgs[s+i].msg_len - 10;
}
return writev(fd, dbuf->write_iovecs, vlen);
}
dgrambuf_t dgrambuf_new(size_t dgram_count, size_t dgram_max_size) {
dgrambuf_t dbuf = calloc(1, sizeof(struct dgrambuf_t));
if (!dbuf) goto fail0;
dbuf->dgram_count = dgram_count;
dbuf->dgram_max_size = dgram_max_size;
dbuf->recv_iovecs = calloc(dgram_count, sizeof(struct iovec));
if (!dbuf->recv_iovecs) goto fail1;
dbuf->write_iovecs = calloc(dgram_count, sizeof(struct iovec));
if (!dbuf->write_iovecs) goto fail2;
dbuf->msgs = calloc(dgram_count, sizeof(struct mmsghdr));
if (!dbuf->msgs) goto fail3;
dbuf->buf = calloc(dgram_count, dgram_max_size);
if (!dbuf->buf) goto fail4;
return dbuf;
fail4: free(dbuf->msgs);
fail3: free(dbuf->write_iovecs);
fail2: free(dbuf->recv_iovecs);
fail1: free(dbuf);
fail0: return 0;
}
void dgrambuf_free(dgrambuf_t *dbuf) {
if (dbuf && *dbuf) {
free((*dbuf)->msgs);
free((*dbuf)->write_iovecs);
free((*dbuf)->recv_iovecs);
free(*dbuf);
}
*dbuf = NULL;
}
size_t dgrambuf_free_count(const dgrambuf_t dbuf) {
if (dbuf->buf_full) {
return 0;
} else if ( dbuf->buf_head < dbuf->buf_tail ) {
return dbuf->buf_tail - dbuf->buf_head - 1;
}// else {
return dbuf->dgram_count - (dbuf->buf_head - dbuf->buf_tail );
//}
}
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