nhrpd/zbuf.c

   1 /* Stream/packet buffer API implementation
   2  * Copyright (c) 2014-2015 Timo Teräs
   3  *
   4  * This file is free software: you may copy, redistribute and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  */
   9
  10 #define _GNU_SOURCE
  11 #include <string.h>
  12 #include <unistd.h>
  13 #include <errno.h>
  14 #include "zassert.h"
  15 #include "zbuf.h"
  16 #include "memory.h"
  17 #include "nhrpd.h"
  18
  19 #define ERRNO_IO_RETRY(EN) (((EN) == EAGAIN) || ((EN) == EWOULDBLOCK) || ((EN) == EINTR))
  20
  21 DEFINE_MTYPE_STATIC(NHRPD, ZBUF_DATA, "NHRPD zbuf data")
  22
  23 struct zbuf *zbuf_alloc(size_t size)
  24 {
  25         struct zbuf *zb;
  26
  27         zb = XMALLOC(MTYPE_ZBUF_DATA, sizeof(*zb) + size);
  28         if (!zb)
  29                 return NULL;
  30
  31         zbuf_init(zb, zb+1, size, 0);
  32         zb->allocated = 1;
  33
  34         return zb;
  35 }
  36
  37 void zbuf_init(struct zbuf *zb, void *buf, size_t len, size_t datalen)
  38 {
  39         *zb = (struct zbuf) {
  40                 .buf = buf,
  41                 .end = (uint8_t *)buf + len,
  42                 .head = buf,
  43                 .tail = (uint8_t *)buf + datalen,
  44         };
  45 }
  46
  47 void zbuf_free(struct zbuf *zb)
  48 {
  49         if (zb->allocated)
  50                 XFREE(MTYPE_ZBUF_DATA, zb);
  51 }
  52
  53 void zbuf_reset(struct zbuf *zb)
  54 {
  55         zb->head = zb->tail = zb->buf;
  56         zb->error = 0;
  57 }
  58
  59 void zbuf_reset_head(struct zbuf *zb, void *ptr)
  60 {
  61         zassert((void*)zb->buf <= ptr && ptr <= (void*)zb->tail);
  62         zb->head = ptr;
  63 }
  64
  65 static void zbuf_remove_headroom(struct zbuf *zb)
  66 {
  67         ssize_t headroom = zbuf_headroom(zb);
  68         if (!headroom)
  69                 return;
  70         memmove(zb->buf, zb->head, zbuf_used(zb));
  71         zb->head -= headroom;
  72         zb->tail -= headroom;
  73 }
  74
  75 ssize_t zbuf_read(struct zbuf *zb, int fd, size_t maxlen)
  76 {
  77         ssize_t r;
  78
  79         if (zb->error)
  80                 return -3;
  81
  82         zbuf_remove_headroom(zb);
  83         if (maxlen > zbuf_tailroom(zb))
  84                 maxlen = zbuf_tailroom(zb);
  85
  86         r = read(fd, zb->tail, maxlen);
  87         if (r > 0) zb->tail += r;
  88         else if (r == 0) r = -2;
  89         else if (r < 0 && ERRNO_IO_RETRY(errno)) r = 0;
  90
  91         return r;
  92 }
  93
  94 ssize_t zbuf_write(struct zbuf *zb, int fd)
  95 {
  96         ssize_t r;
  97
  98         if (zb->error)
  99                 return -3;
 100
 101         r = write(fd, zb->head, zbuf_used(zb));
 102         if (r > 0) {
 103                 zb->head += r;
 104                 if (zb->head == zb->tail)
 105                         zbuf_reset(zb);
 106         }
 107         else if (r == 0) r = -2;
 108         else if (r < 0 && ERRNO_IO_RETRY(errno)) r = 0;
 109
 110         return r;
 111 }
 112
 113 ssize_t zbuf_recv(struct zbuf *zb, int fd)
 114 {
 115         ssize_t r;
 116
 117         if (zb->error)
 118                 return -3;
 119
 120         zbuf_remove_headroom(zb);
 121         r = recv(fd, zb->tail, zbuf_tailroom(zb), 0);
 122         if (r > 0) zb->tail += r;
 123         else if (r == 0) r = -2;
 124         else if (r < 0 && ERRNO_IO_RETRY(errno)) r = 0;
 125         return r;
 126 }
 127
 128 ssize_t zbuf_send(struct zbuf *zb, int fd)
 129 {
 130         ssize_t r;
 131
 132         if (zb->error)
 133                 return -3;
 134
 135         r = send(fd, zb->head, zbuf_used(zb), 0);
 136         if (r >= 0)
 137                 zbuf_reset(zb);
 138
 139         return r;
 140 }
 141
 142 void *zbuf_may_pull_until(struct zbuf *zb, const char *sep, struct zbuf *msg)
 143 {
 144         size_t seplen = strlen(sep), len;
 145         uint8_t *ptr;
 146
 147         ptr = memmem(zb->head, zbuf_used(zb), sep, seplen);
 148         if (!ptr) return NULL;
 149
 150         len = ptr - zb->head + seplen;
 151         zbuf_init(msg, zbuf_pulln(zb, len), len, len);
 152         return msg->head;
 153 }
 154
 155 void zbufq_init(struct zbuf_queue *zbq)
 156 {
 157         *zbq = (struct zbuf_queue) {
 158                 .queue_head = LIST_INITIALIZER(zbq->queue_head),
 159         };
 160 }
 161
 162 void zbufq_reset(struct zbuf_queue *zbq)
 163 {
 164         struct zbuf *buf, *bufn;
 165
 166         list_for_each_entry_safe(buf, bufn, &zbq->queue_head, queue_list) {
 167                 list_del(&buf->queue_list);
 168                 zbuf_free(buf);
 169         }
 170 }
 171
 172 void zbufq_queue(struct zbuf_queue *zbq, struct zbuf *zb)
 173 {
 174         list_add_tail(&zb->queue_list, &zbq->queue_head);
 175 }
 176
 177 int zbufq_write(struct zbuf_queue *zbq, int fd)
 178 {
 179         struct iovec iov[16];
 180         struct zbuf *zb, *zbn;
 181         ssize_t r;
 182         size_t iovcnt = 0;
 183
 184         list_for_each_entry_safe(zb, zbn, &zbq->queue_head, queue_list) {
 185                 iov[iovcnt++] = (struct iovec) {
 186                         .iov_base = zb->head,
 187                         .iov_len = zbuf_used(zb),
 188                 };
 189                 if (iovcnt >= ZEBRA_NUM_OF(iov))
 190                         break;
 191         }
 192
 193         r = writev(fd, iov, iovcnt);
 194         if (r < 0)
 195                 return r;
 196
 197         list_for_each_entry_safe(zb, zbn, &zbq->queue_head, queue_list) {
 198                 if (r < (ssize_t)zbuf_used(zb)) {
 199                         zb->head += r;
 200                         return 1;
 201                 }
 202
 203                 r -= zbuf_used(zb);
 204                 list_del(&zb->queue_list);
 205                 zbuf_free(zb);
 206         }
 207
 208         return 0;
 209 }
 210
 211 void zbuf_copy(struct zbuf *zdst, struct zbuf *zsrc, size_t len)
 212 {
 213         const void *src;
 214         void *dst;
 215
 216         dst = zbuf_pushn(zdst, len);
 217         src = zbuf_pulln(zsrc, len);
 218         if (!dst || !src) return;
 219         memcpy(dst, src, len);
 220 }