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/*
* Packet buffer structure and utilities.
*
* Based on pkt_buff.h from the netsniff-ng toolkit.
*
* Copyright (C) 2015 Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2012 Christoph Jaeger
*
* This file is part of llmnrd.
*
* llmnrd is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2 of the License.
*
* llmnrd 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with llmnrd. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef PKT_H
#define PKT_H
#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include "util.h"
struct pkt {
uint8_t *head;
uint8_t *data;
uint8_t *tail;
size_t size;
};
static inline bool pkt_invariant(struct pkt *p)
{
return p && (p->head <= p->data) && (p->data <= p->tail);
}
static inline struct pkt *pkt_alloc(size_t size)
{
struct pkt *p = xmalloc(sizeof(*q) + size);
uint8_t *data = (uint8_t *)p + sizeof(*p);
p->head = data;
p->data = data;
p->tail = data + size;
p->size = size;
return p;
}
static inline void pkt_free(struct pkt *p)
{
free(p);
}
static inline size_t pkt_len(struct pkt *p)
{
assert(pkt_invariant(p));
return p->tail - p->data;
}
static inline uint8_t *pkt_put(struct pkt *p, size_t len)
{
uint8_t *data = NULL;
assert(pkt_invariant(p));
if (len <= pkt_len(p)) {
data = p->tail;
p->tail += len;
} else
assert(false); /* TODO */
return data;
}
static inline void pkt_put_u16(struct pkt *p, uint16_t val)
{
uint16_t *data = (uint16_t *)pkt_put(p, sizeof(val));
*data = val;
}
static inline void pkt_put_u32(struct pkt *p, uint32_t val)
{
uint32_t *data = (uint32_t *)pkt_put(p, sizeof(val));
*data = val;
}
#endif /* PKT_H */
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