/* * Packet buffer structure and utilities. * * Copyright (C) 2015 Tobias Klauser * * Based on pkt_buff.h from the netsniff-ng toolkit which is: * * 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 . */ #ifndef PKT_H #define PKT_H #include #include #include #include "log.h" #include "util.h" struct pkt { uint8_t *data; uint8_t *tail; size_t size; }; static inline bool pkt_invariant(struct pkt *p) { return p && (p->data <= p->tail); } static inline struct pkt *pkt_alloc(size_t size) { struct pkt *p = xmalloc(sizeof(*p) + size); uint8_t *data = (uint8_t *)p + sizeof(*p); p->data = p->tail = data; p->size = size; return p; } static inline void pkt_free(struct pkt *p) { free(p); } static inline void pkt_reset(struct pkt *p) { assert(pkt_invariant(p)); p->tail = p->data; } 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; assert(pkt_invariant(p)); if (pkt_len(p) + len <= p->size) { data = p->tail; p->tail += len; } else { /* grow packet */ size_t new_size = p->size + len - pkt_len(p); struct pkt *np = xrealloc(p, sizeof(*np) + new_size); log_dbg("Reallocating packet from %zu to %zu bytes\n", p->size, new_size); data = (uint8_t *)np + sizeof(*np); np->data = data; np->tail = data + pkt_len(p); } return data; } #define DEFINE_PKT_PUT(__bitwidth) \ static inline void pkt_put_u##__bitwidth(struct pkt *p, uint##__bitwidth##_t val) \ { \ uint##__bitwidth##_t *data = (uint##__bitwidth##_t *)pkt_put(p, sizeof(val)); \ *data = val; \ } DEFINE_PKT_PUT(8) DEFINE_PKT_PUT(16) DEFINE_PKT_PUT(32) #endif /* PKT_H */ value=''/>
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