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- /*
- This file is part of GNUnet.
- Copyright (C) 2010, 2016, 2017 GNUnet e.V.
- GNUnet is free software: you can redistribute it and/or modify it
- under the terms of the GNU Affero General Public License as published
- by the Free Software Foundation, either version 3 of the License,
- or (at your option) any later version.
- GNUnet 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
- Affero General Public License for more details.
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @file util/mst.c
- * @brief convenience functions for handling inbound message buffers
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet_util_lib.h"
- #if HAVE_UNALIGNED_64_ACCESS
- #define ALIGN_FACTOR 4
- #else
- #define ALIGN_FACTOR 8
- #endif
- #define LOG(kind, ...) GNUNET_log_from (kind, "util-mst", __VA_ARGS__)
- /**
- * Handle to a message stream tokenizer.
- */
- struct GNUNET_MessageStreamTokenizer
- {
- /**
- * Function to call on completed messages.
- */
- GNUNET_MessageTokenizerCallback cb;
- /**
- * Closure for @e cb.
- */
- void *cb_cls;
- /**
- * Size of the buffer (starting at @e hdr).
- */
- size_t curr_buf;
- /**
- * How many bytes in buffer have we already processed?
- */
- size_t off;
- /**
- * How many bytes in buffer are valid right now?
- */
- size_t pos;
- /**
- * Beginning of the buffer. Typed like this to force alignment.
- */
- struct GNUNET_MessageHeader *hdr;
- };
- /**
- * Create a message stream tokenizer.
- *
- * @param cb function to call on completed messages
- * @param cb_cls closure for @a cb
- * @return handle to tokenizer
- */
- struct GNUNET_MessageStreamTokenizer *
- GNUNET_MST_create (GNUNET_MessageTokenizerCallback cb,
- void *cb_cls)
- {
- struct GNUNET_MessageStreamTokenizer *ret;
- ret = GNUNET_new (struct GNUNET_MessageStreamTokenizer);
- ret->hdr = GNUNET_malloc (GNUNET_MIN_MESSAGE_SIZE);
- ret->curr_buf = GNUNET_MIN_MESSAGE_SIZE;
- ret->cb = cb;
- ret->cb_cls = cb_cls;
- return ret;
- }
- /**
- * Add incoming data to the receive buffer and call the
- * callback for all complete messages.
- *
- * @param mst tokenizer to use
- * @param buf input data to add
- * @param size number of bytes in @a buf
- * @param purge should any excess bytes in the buffer be discarded
- * (i.e. for packet-based services like UDP)
- * @param one_shot only call callback once, keep rest of message in buffer
- * @return #GNUNET_OK if we are done processing (need more data)
- * #GNUNET_NO if @a one_shot was set and we have another message ready
- * #GNUNET_SYSERR if the data stream is corrupt
- */
- int
- GNUNET_MST_from_buffer (struct GNUNET_MessageStreamTokenizer *mst,
- const char *buf,
- size_t size,
- int purge,
- int one_shot)
- {
- const struct GNUNET_MessageHeader *hdr;
- size_t delta;
- uint16_t want;
- char *ibuf;
- int need_align;
- unsigned long offset;
- int ret;
- int cbret;
- GNUNET_assert (mst->off <= mst->pos);
- GNUNET_assert (mst->pos <= mst->curr_buf);
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "MST receives %u bytes with %u bytes already in private buffer\n",
- (unsigned int) size,
- (unsigned int) (mst->pos - mst->off));
- ret = GNUNET_OK;
- ibuf = (char *) mst->hdr;
- while (mst->pos > 0)
- {
- do_align:
- GNUNET_assert (mst->pos >= mst->off);
- if ((mst->curr_buf - mst->off < sizeof(struct GNUNET_MessageHeader)) ||
- (0 != (mst->off % ALIGN_FACTOR)))
- {
- /* need to align or need more space */
- mst->pos -= mst->off;
- memmove (ibuf,
- &ibuf[mst->off],
- mst->pos);
- mst->off = 0;
- }
- if (mst->pos - mst->off < sizeof(struct GNUNET_MessageHeader))
- {
- delta
- = GNUNET_MIN (sizeof(struct GNUNET_MessageHeader)
- - (mst->pos - mst->off),
- size);
- GNUNET_memcpy (&ibuf[mst->pos],
- buf,
- delta);
- mst->pos += delta;
- buf += delta;
- size -= delta;
- }
- if (mst->pos - mst->off < sizeof(struct GNUNET_MessageHeader))
- {
- if (purge)
- {
- mst->off = 0;
- mst->pos = 0;
- }
- return GNUNET_OK;
- }
- hdr = (const struct GNUNET_MessageHeader *) &ibuf[mst->off];
- want = ntohs (hdr->size);
- if (want < sizeof(struct GNUNET_MessageHeader))
- {
- GNUNET_break_op (0);
- return GNUNET_SYSERR;
- }
- if ((mst->curr_buf - mst->off < want) &&
- (mst->off > 0))
- {
- /* can get more space by moving */
- mst->pos -= mst->off;
- memmove (ibuf,
- &ibuf[mst->off],
- mst->pos);
- mst->off = 0;
- }
- if (mst->curr_buf < want)
- {
- /* need to get more space by growing buffer */
- GNUNET_assert (0 == mst->off);
- mst->hdr = GNUNET_realloc (mst->hdr,
- want);
- ibuf = (char *) mst->hdr;
- mst->curr_buf = want;
- }
- hdr = (const struct GNUNET_MessageHeader *) &ibuf[mst->off];
- if (mst->pos - mst->off < want)
- {
- delta = GNUNET_MIN (want - (mst->pos - mst->off),
- size);
- GNUNET_assert (mst->pos + delta <= mst->curr_buf);
- GNUNET_memcpy (&ibuf[mst->pos],
- buf,
- delta);
- mst->pos += delta;
- buf += delta;
- size -= delta;
- }
- if (mst->pos - mst->off < want)
- {
- if (purge)
- {
- mst->off = 0;
- mst->pos = 0;
- }
- return GNUNET_OK;
- }
- if (one_shot == GNUNET_SYSERR)
- {
- /* cannot call callback again, but return value saying that
- * we have another full message in the buffer */
- ret = GNUNET_NO;
- goto copy;
- }
- if (one_shot == GNUNET_YES)
- one_shot = GNUNET_SYSERR;
- mst->off += want;
- if (GNUNET_OK !=
- (cbret = mst->cb (mst->cb_cls,
- hdr)))
- {
- if (GNUNET_SYSERR == cbret)
- GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
- "Failure processing message of type %u and size %u\n",
- ntohs (hdr->type),
- ntohs (hdr->size));
- return GNUNET_SYSERR;
- }
- if (mst->off == mst->pos)
- {
- /* reset to beginning of buffer, it's free right now! */
- mst->off = 0;
- mst->pos = 0;
- }
- }
- GNUNET_assert (0 == mst->pos);
- while (size > 0)
- {
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Server-mst has %u bytes left in inbound buffer\n",
- (unsigned int) size);
- if (size < sizeof(struct GNUNET_MessageHeader))
- break;
- offset = (unsigned long) buf;
- need_align = (0 != (offset % ALIGN_FACTOR)) ? GNUNET_YES : GNUNET_NO;
- if (GNUNET_NO == need_align)
- {
- /* can try to do zero-copy and process directly from original buffer */
- hdr = (const struct GNUNET_MessageHeader *) buf;
- want = ntohs (hdr->size);
- if (want < sizeof(struct GNUNET_MessageHeader))
- {
- GNUNET_break_op (0);
- mst->off = 0;
- return GNUNET_SYSERR;
- }
- if (size < want)
- break; /* or not: buffer incomplete, so copy to private buffer... */
- if (one_shot == GNUNET_SYSERR)
- {
- /* cannot call callback again, but return value saying that
- * we have another full message in the buffer */
- ret = GNUNET_NO;
- goto copy;
- }
- if (one_shot == GNUNET_YES)
- one_shot = GNUNET_SYSERR;
- if (GNUNET_OK !=
- (cbret = mst->cb (mst->cb_cls,
- hdr)))
- {
- if (GNUNET_SYSERR == cbret)
- GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
- "Failure processing message of type %u and size %u\n",
- ntohs (hdr->type),
- ntohs (hdr->size));
- return GNUNET_SYSERR;
- }
- buf += want;
- size -= want;
- }
- else
- {
- /* need to copy to private buffer to align;
- * yes, we go a bit more spaghetti than usual here */
- goto do_align;
- }
- }
- copy:
- if ((size > 0) && (! purge))
- {
- if (size + mst->pos > mst->curr_buf)
- {
- mst->hdr = GNUNET_realloc (mst->hdr,
- size + mst->pos);
- ibuf = (char *) mst->hdr;
- mst->curr_buf = size + mst->pos;
- }
- GNUNET_assert (size + mst->pos <= mst->curr_buf);
- GNUNET_memcpy (&ibuf[mst->pos],
- buf,
- size);
- mst->pos += size;
- }
- if (purge)
- {
- mst->off = 0;
- mst->pos = 0;
- }
- LOG (GNUNET_ERROR_TYPE_DEBUG,
- "Server-mst leaves %u bytes in private buffer\n",
- (unsigned int) (mst->pos - mst->off));
- return ret;
- }
- /**
- * Add incoming data to the receive buffer and call the
- * callback for all complete messages.
- *
- * @param mst tokenizer to use
- * @param buf input data to add
- * @param size number of bytes in @a buf
- * @param purge should any excess bytes in the buffer be discarded
- * (i.e. for packet-based services like UDP)
- * @param one_shot only call callback once, keep rest of message in buffer
- * @return #GNUNET_OK if we are done processing (need more data)
- * #GNUNET_NO if one_shot was set and we have another message ready
- * #GNUNET_SYSERR if the data stream is corrupt
- */
- int
- GNUNET_MST_read (struct GNUNET_MessageStreamTokenizer *mst,
- struct GNUNET_NETWORK_Handle *sock,
- int purge,
- int one_shot)
- {
- ssize_t ret;
- size_t left;
- char *buf;
- left = mst->curr_buf - mst->pos;
- buf = (char *) mst->hdr;
- ret = GNUNET_NETWORK_socket_recv (sock,
- &buf[mst->pos],
- left);
- if (-1 == ret)
- {
- if ((EAGAIN == errno) ||
- (EINTR == errno))
- return GNUNET_OK;
- GNUNET_log_strerror (GNUNET_ERROR_TYPE_INFO,
- "recv");
- return GNUNET_SYSERR;
- }
- if (0 == ret)
- {
- /* other side closed connection, treat as error */
- return GNUNET_SYSERR;
- }
- mst->pos += ret;
- return GNUNET_MST_from_buffer (mst,
- NULL,
- 0,
- purge,
- one_shot);
- }
- /**
- * Obtain the next message from the @a mst, assuming that
- * there are more unprocessed messages in the internal buffer
- * of the @a mst.
- *
- * @param mst tokenizer to use
- * @param one_shot only call callback once, keep rest of message in buffer
- * @return #GNUNET_OK if we are done processing (need more data)
- * #GNUNET_NO if one_shot was set and we have another message ready
- * #GNUNET_SYSERR if the data stream is corrupt
- */
- int
- GNUNET_MST_next (struct GNUNET_MessageStreamTokenizer *mst,
- int one_shot)
- {
- return GNUNET_MST_from_buffer (mst,
- NULL,
- 0,
- GNUNET_NO,
- one_shot);
- }
- /**
- * Destroys a tokenizer.
- *
- * @param mst tokenizer to destroy
- */
- void
- GNUNET_MST_destroy (struct GNUNET_MessageStreamTokenizer *mst)
- {
- GNUNET_free (mst->hdr);
- GNUNET_free (mst);
- }
- /* end of server_mst.c */
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