sockbuf.c

00001 /*
00002  * Copyright (c) 2016-2017, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 
00018 #include "nsconfig.h"
00019 #include "ns_trace.h"
00020 #include <string.h>
00021 #include "Core/include/sockbuf.h"
00022 
00023 #define TRACE_GROUP "sbuf"
00024 
00025 void sockbuf_init(sockbuf_t *sb)
00026 {
00027     memset(sb, 0, sizeof *sb);
00028     ns_list_init(&sb->bufs);
00029 }
00030 
00031 /* Add buf to counters */
00032 void sockbuf_alloc(sockbuf_t *sb, const buffer_t *buf)
00033 {
00034     sb->buf_overhead_bytes += sizeof *buf + buf->size ;
00035     sb->data_bytes += buffer_data_length(buf);
00036 }
00037 
00038 /* Remove buf from counters */
00039 void sockbuf_free(sockbuf_t *sb, const buffer_t *buf)
00040 {
00041     sb->buf_overhead_bytes -= sizeof *buf + buf->size ;
00042     sb->data_bytes -= buffer_data_length(buf);
00043 }
00044 
00045 void sockbuf_append(sockbuf_t *sb, buffer_t *buf)
00046 {
00047     // Nasty little one - if the buffer references the socket (as is likely on
00048     // entry), it might stop a socket with queued data ever being freed. Avoid
00049     // this trap. Should be no need for socket pointer if on a queue.
00050     buffer_socket_set(buf, NULL);
00051     sockbuf_alloc(sb, buf);
00052     ns_list_add_to_end(&sb->bufs, buf);
00053 }
00054 
00055 /* Try to avoid totally wasting space for streams. Overhead of buffer_t
00056  * still rather large - we don't actually want any metadata at all...
00057  */
00058 void sockbuf_append_and_compress(sockbuf_t *sb, buffer_t *buf)
00059 {
00060     if (buffer_data_length(buf) == 0) {
00061         buffer_free(buf);
00062         return;
00063     }
00064 
00065     buffer_t *last = ns_list_get_last(&sb->bufs);
00066     if (last) {
00067         uint16_t new_len = buffer_data_length(buf);
00068         uint32_t total = buffer_data_length(last) + new_len;
00069         if (total <= last->size) {
00070             // Pack down destination buffer if necessary
00071             if (buffer_data_free_length(last) < new_len) {
00072                 uint16_t last_len = buffer_data_length(last);
00073                 memmove(last->buf , buffer_data_pointer(last), last_len);
00074                 last->buf_ptr  = 0;
00075                 last->buf_end  = last_len;
00076             }
00077             // Add in the data, and add to data count
00078             buffer_data_add(last, buffer_data_pointer(buf), new_len);
00079             sb->data_bytes += new_len;
00080             // Free source buffer
00081             buffer_free(buf);
00082             return;
00083         }
00084     }
00085     sockbuf_append(sb, buf);
00086 }
00087 
00088 /* Drop len bytes of data from the front of the queue */
00089 void sockbuf_drop(sockbuf_t *sb, uint32_t len)
00090 {
00091     while (len) {
00092         buffer_t *buf = ns_list_get_first(&sb->bufs);
00093         if (!buf) {
00094             tr_err("sockbuf_drop");
00095             return;
00096         }
00097         if ((uint32_t) buffer_data_length(buf) > len) {
00098             buffer_data_strip_header(buf, len);
00099             sb->data_bytes -= len;
00100             break;
00101         }
00102         len -= buffer_data_length(buf);
00103         sockbuf_free(sb, buf);
00104         ns_list_remove(&sb->bufs, buf);
00105         buffer_free(buf);
00106     }
00107 }
00108 
00109 /* Drop first buffer from the front of the queue */
00110 void sockbuf_drop_first(sockbuf_t *sb)
00111 {
00112     buffer_t *buf = ns_list_get_first(&sb->bufs);
00113     if (buf) {
00114         sockbuf_free(sb, buf);
00115         ns_list_remove(&sb->bufs, buf);
00116         buffer_free(buf);
00117     }
00118 }
00119 
00120 void sockbuf_flush(sockbuf_t *sb)
00121 {
00122     buffer_free_list(&sb->bufs);
00123     sb->buf_overhead_bytes = sb->data_bytes = 0;
00124 }
00125 
00126 bool sockbuf_reserve(sockbuf_t *sb, uint32_t space)
00127 {
00128     /* Arbitrary limit for now, just avoids overflow nonsense */
00129     if (space >= 0x10000) {
00130         return false;
00131     }
00132     sb->data_byte_limit = space;
00133     sb->buf_overhead_byte_limit = space * 2; // BSD 4.4-style. Does it work for our buffers though?
00134     if (sb->low_water_mark < 1) {
00135         sb->low_water_mark = 1;
00136     }
00137     if (sb->low_water_mark > sb->data_byte_limit) {
00138         sb->low_water_mark = sb->data_byte_limit;
00139     }
00140 
00141     return true;
00142 }
00143 
00144 /* Note that space could be negative if we've overfilled - everything handled signed to catch this */
00145 int32_t sockbuf_space(const sockbuf_t *sb)
00146 {
00147     int32_t data_space = (int32_t) sb->data_byte_limit - (int32_t) sb->data_bytes;
00148     int32_t buf_space = (int32_t) sb->buf_overhead_byte_limit - (int32_t) sb->buf_overhead_bytes;
00149     return data_space < buf_space ? data_space : buf_space;
00150 }
00151 
00152 void sockbuf_check(sockbuf_t *sb)
00153 {
00154     uint32_t data = 0;
00155     uint32_t overhead = 0;
00156     ns_list_foreach(buffer_t, buf, &sb->bufs) {
00157         data += buffer_data_length(buf);
00158         overhead += sizeof *buf + buf->size ;
00159     }
00160 
00161     if (sb->data_bytes != data || sb->buf_overhead_bytes != overhead) {
00162         tr_err("data=%"PRIu32" actual=%"PRIu32", overhead=%"PRIu32" actual=%"PRIu32,
00163                sb->data_bytes, data, sb->buf_overhead_bytes, overhead);
00164         sb->data_bytes = data;
00165         sb->buf_overhead_bytes = overhead;
00166     }
00167 }