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/*
* Ouroboros - Copyright (C) 2016 - 2024
*
* Ring buffer implementations for incoming packets
*
* Dimitri Staessens <dimitri@ouroboros.rocks>
* Sander Vrijders <sander@ouroboros.rocks>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* version 2.1 as published by the Free Software Foundation.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., http://www.fsf.org/about/contact/.
*/
#define _POSIX_C_SOURCE 200809L
#include "config.h"
#include <ouroboros/shm_rbuff.h>
#include <ouroboros/lockfile.h>
#include <ouroboros/errno.h>
#include <ouroboros/fccntl.h>
#include <ouroboros/pthread.h>
#include <ouroboros/time.h>
#include <assert.h>
#include <fcntl.h>
#include <signal.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#define FN_MAX_CHARS 255
#define SHM_RB_FILE_SIZE ((SHM_RBUFF_SIZE) * sizeof(ssize_t) \
+ 3 * sizeof(size_t) \
+ sizeof(pthread_mutex_t) \
+ 2 * sizeof (pthread_cond_t))
#define shm_rbuff_used(rb) ((*rb->head + (SHM_RBUFF_SIZE) - *rb->tail) \
& ((SHM_RBUFF_SIZE) - 1))
#define shm_rbuff_free(rb) (shm_rbuff_used(rb) + 1 < (SHM_RBUFF_SIZE))
#define shm_rbuff_empty(rb) (*rb->head == *rb->tail)
#define head_el_ptr(rb) (rb->shm_base + *rb->head)
#define tail_el_ptr(rb) (rb->shm_base + *rb->tail)
struct shm_rbuff {
ssize_t * shm_base; /* start of entry */
size_t * head; /* start of ringbuffer head */
size_t * tail; /* start of ringbuffer tail */
size_t * acl; /* access control */
pthread_mutex_t * lock; /* lock all free space in shm */
pthread_cond_t * add; /* packet arrived */
pthread_cond_t * del; /* packet removed */
pid_t pid; /* pid of the owner */
int flow_id; /* flow_id of the flow */
};
#define MM_FLAGS (PROT_READ | PROT_WRITE)
static struct shm_rbuff * rbuff_create(pid_t pid,
int flow_id,
int flags)
{
struct shm_rbuff * rb;
int fd;
ssize_t * shm_base;
char fn[FN_MAX_CHARS];
sprintf(fn, SHM_RBUFF_PREFIX "%d.%d", pid, flow_id);
rb = malloc(sizeof(*rb));
if (rb == NULL)
goto fail_malloc;
fd = shm_open(fn, flags, 0666);
if (fd == -1)
goto fail_open;
if ((flags & O_CREAT) && ftruncate(fd, SHM_RB_FILE_SIZE) < 0)
goto fail_truncate;
shm_base = mmap(NULL, SHM_RB_FILE_SIZE, MM_FLAGS, MAP_SHARED, fd, 0);
if (shm_base == MAP_FAILED)
goto fail_truncate;
close(fd);
rb->shm_base = shm_base;
rb->head = (size_t *) (rb->shm_base + (SHM_RBUFF_SIZE));
rb->tail = rb->head + 1;
rb->acl = rb->tail + 1;
rb->lock = (pthread_mutex_t *) (rb->acl + 1);
rb->add = (pthread_cond_t *) (rb->lock + 1);
rb->del = rb->add + 1;
rb->pid = pid;
rb->flow_id = flow_id;
return rb;
fail_truncate:
close(fd);
if (flags & O_CREAT)
shm_unlink(fn);
fail_open:
free(rb);
fail_malloc:
return NULL;
}
static void rbuff_destroy(struct shm_rbuff * rb)
{
munmap(rb->shm_base, SHM_RB_FILE_SIZE);
free(rb);
}
struct shm_rbuff * shm_rbuff_create(pid_t pid,
int flow_id)
{
struct shm_rbuff * rb;
pthread_mutexattr_t mattr;
pthread_condattr_t cattr;
mode_t mask;
mask = umask(0);
rb = rbuff_create(pid, flow_id, O_CREAT | O_EXCL | O_RDWR);
umask(mask);
if (rb == NULL)
goto fail_rb;
if (pthread_mutexattr_init(&mattr))
goto fail_mattr;
pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
#ifdef HAVE_ROBUST_MUTEX
pthread_mutexattr_setrobust(&mattr, PTHREAD_MUTEX_ROBUST);
#endif
if (pthread_mutex_init(rb->lock, &mattr))
goto fail_mutex;
if (pthread_condattr_init(&cattr))
goto fail_cattr;
pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED);
#ifndef __APPLE__
pthread_condattr_setclock(&cattr, PTHREAD_COND_CLOCK);
#endif
if (pthread_cond_init(rb->add, &cattr))
goto fail_add;
if (pthread_cond_init(rb->del, &cattr))
goto fail_del;
*rb->acl = ACL_RDWR;
*rb->head = 0;
*rb->tail = 0;
rb->pid = pid;
rb->flow_id = flow_id;
pthread_mutexattr_destroy(&mattr);
pthread_condattr_destroy(&cattr);
return rb;
fail_del:
pthread_cond_destroy(rb->add);
fail_add:
pthread_condattr_destroy(&cattr);
fail_cattr:
pthread_mutex_destroy(rb->lock);
fail_mutex:
pthread_mutexattr_destroy(&mattr);
fail_mattr:
shm_rbuff_destroy(rb);
fail_rb:
return NULL;
}
struct shm_rbuff * shm_rbuff_open(pid_t pid,
int flow_id)
{
return rbuff_create(pid, flow_id, O_RDWR);
}
void shm_rbuff_close(struct shm_rbuff * rb)
{
assert(rb);
rbuff_destroy(rb);
}
#if (defined(SHM_RBUFF_LOCKLESS) && \
(defined(__GNUC__) || defined (__clang__)))
#include "shm_rbuff_ll.c"
#else
#include "shm_rbuff_pthr.c"
#endif
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