2 * Copyright (C) 2013 Michael Brown <mbrown@fensystems.co.uk>.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
29 #include <ipxe/retry.h>
30 #include <ipxe/timer.h>
31 #include <ipxe/ipstat.h>
32 #include <ipxe/fragment.h>
41 * Expire fragment reassembly buffer
43 * @v timer Retry timer
44 * @v fail Failure indicator
46 static void fragment_expired ( struct retry_timer *timer, int fail __unused ) {
47 struct fragment *fragment =
48 container_of ( timer, struct fragment, timer );
50 DBGC ( fragment, "FRAG %p expired\n", fragment );
51 free_iob ( fragment->iobuf );
52 list_del ( &fragment->list );
53 fragment->fragments->stats->reasm_fails++;
58 * Find fragment reassembly buffer
60 * @v fragments Fragment reassembler
62 * @v hdrlen Length of non-fragmentable potion of I/O buffer
63 * @ret fragment Fragment reassembly buffer, or NULL if not found
65 static struct fragment * fragment_find ( struct fragment_reassembler *fragments,
66 struct io_buffer *iobuf,
68 struct fragment *fragment;
70 list_for_each_entry ( fragment, &fragments->list, list ) {
71 if ( fragments->is_fragment ( fragment, iobuf, hdrlen ) )
80 * @v fragments Fragment reassembler
82 * @v hdrlen Length of non-fragmentable potion of I/O buffer
83 * @ret iobuf Reassembled packet, or NULL
85 * This function takes ownership of the I/O buffer. Note that the
86 * length of the non-fragmentable portion may be modified.
88 struct io_buffer * fragment_reassemble ( struct fragment_reassembler *fragments,
89 struct io_buffer *iobuf,
91 struct fragment *fragment;
92 struct io_buffer *new_iobuf;
95 size_t expected_offset;
98 /* Update statistics */
99 fragments->stats->reasm_reqds++;
101 /* Find matching fragment reassembly buffer, if any */
102 fragment = fragment_find ( fragments, iobuf, *hdrlen );
104 /* Drop out-of-order fragments */
105 offset = fragments->fragment_offset ( iobuf, *hdrlen );
106 expected_offset = ( fragment ? ( iob_len ( fragment->iobuf ) -
107 fragment->hdrlen ) : 0 );
108 if ( offset != expected_offset ) {
109 DBGC ( fragment, "FRAG %p dropping out-of-sequence fragment "
110 "[%zd,%zd), expected [%zd,...)\n", fragment, offset,
111 ( offset + iob_len ( iobuf ) - *hdrlen ),
116 /* Create or extend fragment reassembly buffer as applicable */
119 /* Create new fragment reassembly buffer */
120 fragment = zalloc ( sizeof ( *fragment ) );
123 list_add ( &fragment->list, &fragments->list );
124 fragment->iobuf = iobuf;
125 fragment->hdrlen = *hdrlen;
126 timer_init ( &fragment->timer, fragment_expired, NULL );
127 fragment->fragments = fragments;
128 DBGC ( fragment, "FRAG %p [0,%zd)\n", fragment,
129 ( iob_len ( iobuf ) - *hdrlen ) );
133 /* Check if this is the final fragment */
134 more_frags = fragments->more_fragments ( iobuf, *hdrlen );
135 DBGC ( fragment, "FRAG %p [%zd,%zd)%s\n", fragment,
136 offset, ( offset + iob_len ( iobuf ) - *hdrlen ),
137 ( more_frags ? "" : " complete" ) );
139 /* Extend fragment reassembly buffer. Preserve I/O
140 * buffer headroom to allow for code which modifies
141 * and resends the buffer (e.g. ICMP echo responses).
143 iob_pull ( iobuf, *hdrlen );
144 new_len = ( iob_headroom ( fragment->iobuf ) +
145 iob_len ( fragment->iobuf ) + iob_len ( iobuf ) );
146 new_iobuf = alloc_iob ( new_len );
148 DBGC ( fragment, "FRAG %p could not extend reassembly "
149 "buffer to %zd bytes\n", fragment, new_len );
152 iob_reserve ( new_iobuf, iob_headroom ( fragment->iobuf ) );
153 memcpy ( iob_put ( new_iobuf, iob_len ( fragment->iobuf ) ),
154 fragment->iobuf->data, iob_len ( fragment->iobuf ) );
155 memcpy ( iob_put ( new_iobuf, iob_len ( iobuf ) ),
156 iobuf->data, iob_len ( iobuf ) );
157 free_iob ( fragment->iobuf );
158 fragment->iobuf = new_iobuf;
161 /* Stop fragment reassembly timer */
162 stop_timer ( &fragment->timer );
164 /* If this is the final fragment, return it */
165 if ( ! more_frags ) {
166 iobuf = fragment->iobuf;
167 *hdrlen = fragment->hdrlen;
168 list_del ( &fragment->list );
170 fragments->stats->reasm_oks++;
175 /* (Re)start fragment reassembly timer */
176 start_timer_fixed ( &fragment->timer, FRAGMENT_TIMEOUT );
181 fragments->stats->reasm_fails++;