1 /** 2 * @file 3 * pbuf API 4 */ 5 6 /* 7 * Copyright (c) 2001-2004 Swedish Institute of Computer Science. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without modification, 11 * are permitted provided that the following conditions are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright notice, 14 * this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 3. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 24 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 29 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 30 * OF SUCH DAMAGE. 31 * 32 * This file is part of the lwIP TCP/IP stack. 33 * 34 * Author: Adam Dunkels <[email protected]> 35 * 36 */ 37 38 #ifndef LWIP_HDR_PBUF_H 39 #define LWIP_HDR_PBUF_H 40 41 #include "lwip/opt.h" 42 #include "lwip/err.h" 43 44 #ifdef __cplusplus 45 extern "C" { 46 #endif 47 48 /** LWIP_SUPPORT_CUSTOM_PBUF==1: Custom pbufs behave much like their pbuf type 49 * but they are allocated by external code (initialised by calling 50 * pbuf_alloced_custom()) and when pbuf_free gives up their last reference, they 51 * are freed by calling pbuf_custom->custom_free_function(). 52 * Currently, the pbuf_custom code is only needed for one specific configuration 53 * of IP_FRAG, unless required by external driver/application code. */ 54 #ifndef LWIP_SUPPORT_CUSTOM_PBUF 55 #define LWIP_SUPPORT_CUSTOM_PBUF ((IP_FRAG && !LWIP_NETIF_TX_SINGLE_PBUF) || (LWIP_IPV6 && LWIP_IPV6_FRAG)) 56 #endif 57 58 /* @todo: We need a mechanism to prevent wasting memory in every pbuf 59 (TCP vs. UDP, IPv4 vs. IPv6: UDP/IPv4 packets may waste up to 28 bytes) */ 60 61 #define PBUF_TRANSPORT_HLEN 20 62 #if LWIP_IPV6 63 #define PBUF_IP_HLEN 40 64 #else 65 #define PBUF_IP_HLEN 20 66 #endif 67 68 /** 69 * @ingroup pbuf 70 * Enumeration of pbuf layers 71 */ 72 typedef enum { 73 /** Includes spare room for transport layer header, e.g. UDP header. 74 * Use this if you intend to pass the pbuf to functions like udp_send(). 75 */ 76 PBUF_TRANSPORT, 77 /** Includes spare room for IP header. 78 * Use this if you intend to pass the pbuf to functions like raw_send(). 79 */ 80 PBUF_IP, 81 /** Includes spare room for link layer header (ethernet header). 82 * Use this if you intend to pass the pbuf to functions like ethernet_output(). 83 * @see PBUF_LINK_HLEN 84 */ 85 PBUF_LINK, 86 /** Includes spare room for additional encapsulation header before ethernet 87 * headers (e.g. 802.11). 88 * Use this if you intend to pass the pbuf to functions like netif->linkoutput(). 89 * @see PBUF_LINK_ENCAPSULATION_HLEN 90 */ 91 PBUF_RAW_TX, 92 /** Use this for input packets in a netif driver when calling netif->input() 93 * in the most common case - ethernet-layer netif driver. */ 94 PBUF_RAW 95 } pbuf_layer; 96 97 /** 98 * @ingroup pbuf 99 * Enumeration of pbuf types 100 */ 101 typedef enum { 102 /** pbuf data is stored in RAM, used for TX mostly, struct pbuf and its payload 103 are allocated in one piece of contiguous memory (so the first payload byte 104 can be calculated from struct pbuf). 105 pbuf_alloc() allocates PBUF_RAM pbufs as unchained pbufs (although that might 106 change in future versions). 107 This should be used for all OUTGOING packets (TX).*/ 108 PBUF_RAM, 109 /** pbuf data is stored in ROM, i.e. struct pbuf and its payload are located in 110 totally different memory areas. Since it points to ROM, payload does not 111 have to be copied when queued for transmission. */ 112 PBUF_ROM, 113 /** pbuf comes from the pbuf pool. Much like PBUF_ROM but payload might change 114 so it has to be duplicated when queued before transmitting, depending on 115 who has a 'ref' to it. */ 116 PBUF_REF, 117 /** pbuf payload refers to RAM. This one comes from a pool and should be used 118 for RX. Payload can be chained (scatter-gather RX) but like PBUF_RAM, struct 119 pbuf and its payload are allocated in one piece of contiguous memory (so 120 the first payload byte can be calculated from struct pbuf). 121 Don't use this for TX, if the pool becomes empty e.g. because of TCP queuing, 122 you are unable to receive TCP acks! */ 123 PBUF_POOL 124 } pbuf_type; 125 126 127 /** indicates this packet's data should be immediately passed to the application */ 128 #define PBUF_FLAG_PUSH 0x01U 129 /** indicates this is a custom pbuf: pbuf_free calls pbuf_custom->custom_free_function() 130 when the last reference is released (plus custom PBUF_RAM cannot be trimmed) */ 131 #define PBUF_FLAG_IS_CUSTOM 0x02U 132 /** indicates this pbuf is UDP multicast to be looped back */ 133 #define PBUF_FLAG_MCASTLOOP 0x04U 134 /** indicates this pbuf was received as link-level broadcast */ 135 #define PBUF_FLAG_LLBCAST 0x08U 136 /** indicates this pbuf was received as link-level multicast */ 137 #define PBUF_FLAG_LLMCAST 0x10U 138 /** indicates this pbuf includes a TCP FIN flag */ 139 #define PBUF_FLAG_TCP_FIN 0x20U 140 141 /** Main packet buffer struct */ 142 struct pbuf { 143 /** next pbuf in singly linked pbuf chain */ 144 struct pbuf *next; 145 146 /** pointer to the actual data in the buffer */ 147 void *payload; 148 149 /** 150 * total length of this buffer and all next buffers in chain 151 * belonging to the same packet. 152 * 153 * For non-queue packet chains this is the invariant: 154 * p->tot_len == p->len + (p->next? p->next->tot_len: 0) 155 */ 156 u16_t tot_len; 157 158 /** length of this buffer */ 159 u16_t len; 160 161 /** pbuf_type as u8_t instead of enum to save space */ 162 u8_t /*pbuf_type*/ type; 163 164 /** misc flags */ 165 u8_t flags; 166 167 /** 168 * the reference count always equals the number of pointers 169 * that refer to this pbuf. This can be pointers from an application, 170 * the stack itself, or pbuf->next pointers from a chain. 171 */ 172 u16_t ref; 173 }; 174 175 176 /** Helper struct for const-correctness only. 177 * The only meaning of this one is to provide a const payload pointer 178 * for PBUF_ROM type. 179 */ 180 struct pbuf_rom { 181 /** next pbuf in singly linked pbuf chain */ 182 struct pbuf *next; 183 184 /** pointer to the actual data in the buffer */ 185 const void *payload; 186 }; 187 188 #if LWIP_SUPPORT_CUSTOM_PBUF 189 /** Prototype for a function to free a custom pbuf */ 190 typedef void (*pbuf_free_custom_fn)(struct pbuf *p); 191 192 /** A custom pbuf: like a pbuf, but following a function pointer to free it. */ 193 struct pbuf_custom { 194 /** The actual pbuf */ 195 struct pbuf pbuf; 196 /** This function is called when pbuf_free deallocates this pbuf(_custom) */ 197 pbuf_free_custom_fn custom_free_function; 198 }; 199 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */ 200 201 /** Define this to 0 to prevent freeing ooseq pbufs when the PBUF_POOL is empty */ 202 #ifndef PBUF_POOL_FREE_OOSEQ 203 #define PBUF_POOL_FREE_OOSEQ 1 204 #endif /* PBUF_POOL_FREE_OOSEQ */ 205 #if LWIP_TCP && TCP_QUEUE_OOSEQ && NO_SYS && PBUF_POOL_FREE_OOSEQ 206 extern volatile u8_t pbuf_free_ooseq_pending; 207 void pbuf_free_ooseq(void); 208 /** When not using sys_check_timeouts(), call PBUF_CHECK_FREE_OOSEQ() 209 at regular intervals from main level to check if ooseq pbufs need to be 210 freed! */ 211 #define PBUF_CHECK_FREE_OOSEQ() do { if(pbuf_free_ooseq_pending) { \ 212 /* pbuf_alloc() reported PBUF_POOL to be empty -> try to free some \ 213 ooseq queued pbufs now */ \ 214 pbuf_free_ooseq(); }}while(0) 215 #else /* LWIP_TCP && TCP_QUEUE_OOSEQ && NO_SYS && PBUF_POOL_FREE_OOSEQ */ 216 /* Otherwise declare an empty PBUF_CHECK_FREE_OOSEQ */ 217 #define PBUF_CHECK_FREE_OOSEQ() 218 #endif /* LWIP_TCP && TCP_QUEUE_OOSEQ && NO_SYS && PBUF_POOL_FREE_OOSEQ*/ 219 220 /* Initializes the pbuf module. This call is empty for now, but may not be in future. */ 221 #define pbuf_init() 222 223 struct pbuf *pbuf_alloc(pbuf_layer l, u16_t length, pbuf_type type); 224 #if LWIP_SUPPORT_CUSTOM_PBUF 225 struct pbuf *pbuf_alloced_custom(pbuf_layer l, u16_t length, pbuf_type type, 226 struct pbuf_custom *p, void *payload_mem, 227 u16_t payload_mem_len); 228 #endif /* LWIP_SUPPORT_CUSTOM_PBUF */ 229 void pbuf_realloc(struct pbuf *p, u16_t size); 230 u8_t pbuf_header(struct pbuf *p, s16_t header_size); 231 u8_t pbuf_header_force(struct pbuf *p, s16_t header_size); 232 void pbuf_ref(struct pbuf *p); 233 u8_t pbuf_free(struct pbuf *p); 234 u16_t pbuf_clen(const struct pbuf *p); 235 void pbuf_cat(struct pbuf *head, struct pbuf *tail); 236 void pbuf_chain(struct pbuf *head, struct pbuf *tail); 237 struct pbuf *pbuf_dechain(struct pbuf *p); 238 err_t pbuf_copy(struct pbuf *p_to, const struct pbuf *p_from); 239 u16_t pbuf_copy_partial(const struct pbuf *p, void *dataptr, u16_t len, u16_t offset); 240 err_t pbuf_take(struct pbuf *buf, const void *dataptr, u16_t len); 241 err_t pbuf_take_at(struct pbuf *buf, const void *dataptr, u16_t len, u16_t offset); 242 struct pbuf *pbuf_skip(struct pbuf* in, u16_t in_offset, u16_t* out_offset); 243 struct pbuf *pbuf_coalesce(struct pbuf *p, pbuf_layer layer); 244 #if LWIP_CHECKSUM_ON_COPY 245 err_t pbuf_fill_chksum(struct pbuf *p, u16_t start_offset, const void *dataptr, 246 u16_t len, u16_t *chksum); 247 #endif /* LWIP_CHECKSUM_ON_COPY */ 248 #if LWIP_TCP && TCP_QUEUE_OOSEQ && LWIP_WND_SCALE 249 void pbuf_split_64k(struct pbuf *p, struct pbuf **rest); 250 #endif /* LWIP_TCP && TCP_QUEUE_OOSEQ && LWIP_WND_SCALE */ 251 252 u8_t pbuf_get_at(const struct pbuf* p, u16_t offset); 253 int pbuf_try_get_at(const struct pbuf* p, u16_t offset); 254 void pbuf_put_at(struct pbuf* p, u16_t offset, u8_t data); 255 u16_t pbuf_memcmp(const struct pbuf* p, u16_t offset, const void* s2, u16_t n); 256 u16_t pbuf_memfind(const struct pbuf* p, const void* mem, u16_t mem_len, u16_t start_offset); 257 u16_t pbuf_strstr(const struct pbuf* p, const char* substr); 258 259 #ifdef __cplusplus 260 } 261 #endif 262 263 #endif /* LWIP_HDR_PBUF_H */ 264