summaryrefslogtreecommitdiff
path: root/lib/librte_ip_frag/rte_ipv4_fragmentation.c
blob: 8c5f5ec4ab7199551e6e70702190bfc72a14fd6e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stddef.h>
#include <errno.h>

#include <rte_memcpy.h>
#include <rte_mempool.h>
#include <rte_debug.h>

#include "ip_frag_common.h"

/* Fragment Offset */
#define	IPV4_HDR_DF_SHIFT			14
#define	IPV4_HDR_MF_SHIFT			13
#define	IPV4_HDR_FO_SHIFT			3

#define	IPV4_HDR_DF_MASK			(1 << IPV4_HDR_DF_SHIFT)
#define	IPV4_HDR_MF_MASK			(1 << IPV4_HDR_MF_SHIFT)

#define	IPV4_HDR_FO_ALIGN			(1 << IPV4_HDR_FO_SHIFT)

static inline void __fill_ipv4hdr_frag(struct ipv4_hdr *dst,
		const struct ipv4_hdr *src, uint16_t len, uint16_t fofs,
		uint16_t dofs, uint32_t mf)
{
	rte_memcpy(dst, src, sizeof(*dst));
	fofs = (uint16_t)(fofs + (dofs >> IPV4_HDR_FO_SHIFT));
	fofs = (uint16_t)(fofs | mf << IPV4_HDR_MF_SHIFT);
	dst->fragment_offset = rte_cpu_to_be_16(fofs);
	dst->total_length = rte_cpu_to_be_16(len);
	dst->hdr_checksum = 0;
}

static inline void __free_fragments(struct rte_mbuf *mb[], uint32_t num)
{
	uint32_t i;
	for (i = 0; i != num; i++)
		rte_pktmbuf_free(mb[i]);
}

/**
 * IPv4 fragmentation.
 *
 * This function implements the fragmentation of IPv4 packets.
 *
 * @param pkt_in
 *   The input packet.
 * @param pkts_out
 *   Array storing the output fragments.
 * @param mtu_size
 *   Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv4
 *   datagrams. This value includes the size of the IPv4 header.
 * @param pool_direct
 *   MBUF pool used for allocating direct buffers for the output fragments.
 * @param pool_indirect
 *   MBUF pool used for allocating indirect buffers for the output fragments.
 * @return
 *   Upon successful completion - number of output fragments placed
 *   in the pkts_out array.
 *   Otherwise - (-1) * <errno>.
 */
int32_t
rte_ipv4_fragment_packet(struct rte_mbuf *pkt_in,
	struct rte_mbuf **pkts_out,
	uint16_t nb_pkts_out,
	uint16_t mtu_size,
	struct rte_mempool *pool_direct,
	struct rte_mempool *pool_indirect)
{
	struct rte_mbuf *in_seg = NULL;
	struct ipv4_hdr *in_hdr;
	uint32_t out_pkt_pos, in_seg_data_pos;
	uint32_t more_in_segs;
	uint16_t fragment_offset, flag_offset, frag_size;
	uint16_t frag_bytes_remaining;

	/*
	 * Ensure the IP payload length of all fragments is aligned to a
	 * multiple of 8 bytes as per RFC791 section 2.3.
	 */
	frag_size = RTE_ALIGN_FLOOR((mtu_size - sizeof(struct ipv4_hdr)),
				    IPV4_HDR_FO_ALIGN);

	in_hdr = rte_pktmbuf_mtod(pkt_in, struct ipv4_hdr *);
	flag_offset = rte_cpu_to_be_16(in_hdr->fragment_offset);

	/* If Don't Fragment flag is set */
	if (unlikely ((flag_offset & IPV4_HDR_DF_MASK) != 0))
		return -ENOTSUP;

	/* Check that pkts_out is big enough to hold all fragments */
	if (unlikely(frag_size * nb_pkts_out <
	    (uint16_t)(pkt_in->pkt_len - sizeof (struct ipv4_hdr))))
		return -EINVAL;

	in_seg = pkt_in;
	in_seg_data_pos = sizeof(struct ipv4_hdr);
	out_pkt_pos = 0;
	fragment_offset = 0;

	more_in_segs = 1;
	while (likely(more_in_segs)) {
		struct rte_mbuf *out_pkt = NULL, *out_seg_prev = NULL;
		uint32_t more_out_segs;
		struct ipv4_hdr *out_hdr;

		/* Allocate direct buffer */
		out_pkt = rte_pktmbuf_alloc(pool_direct);
		if (unlikely(out_pkt == NULL)) {
			__free_fragments(pkts_out, out_pkt_pos);
			return -ENOMEM;
		}

		/* Reserve space for the IP header that will be built later */
		out_pkt->data_len = sizeof(struct ipv4_hdr);
		out_pkt->pkt_len = sizeof(struct ipv4_hdr);
		frag_bytes_remaining = frag_size;

		out_seg_prev = out_pkt;
		more_out_segs = 1;
		while (likely(more_out_segs && more_in_segs)) {
			struct rte_mbuf *out_seg = NULL;
			uint32_t len;

			/* Allocate indirect buffer */
			out_seg = rte_pktmbuf_alloc(pool_indirect);
			if (unlikely(out_seg == NULL)) {
				rte_pktmbuf_free(out_pkt);
				__free_fragments(pkts_out, out_pkt_pos);
				return -ENOMEM;
			}
			out_seg_prev->next = out_seg;
			out_seg_prev = out_seg;

			/* Prepare indirect buffer */
			rte_pktmbuf_attach(out_seg, in_seg);
			len = frag_bytes_remaining;
			if (len > (in_seg->data_len - in_seg_data_pos)) {
				len = in_seg->data_len - in_seg_data_pos;
			}
			out_seg->data_off = in_seg->data_off + in_seg_data_pos;
			out_seg->data_len = (uint16_t)len;
			out_pkt->pkt_len = (uint16_t)(len +
			    out_pkt->pkt_len);
			out_pkt->nb_segs += 1;
			in_seg_data_pos += len;
			frag_bytes_remaining -= len;

			/* Current output packet (i.e. fragment) done ? */
			if (unlikely(frag_bytes_remaining == 0))
				more_out_segs = 0;

			/* Current input segment done ? */
			if (unlikely(in_seg_data_pos == in_seg->data_len)) {
				in_seg = in_seg->next;
				in_seg_data_pos = 0;

				if (unlikely(in_seg == NULL))
					more_in_segs = 0;
			}
		}

		/* Build the IP header */

		out_hdr = rte_pktmbuf_mtod(out_pkt, struct ipv4_hdr *);

		__fill_ipv4hdr_frag(out_hdr, in_hdr,
		    (uint16_t)out_pkt->pkt_len,
		    flag_offset, fragment_offset, more_in_segs);

		fragment_offset = (uint16_t)(fragment_offset +
		    out_pkt->pkt_len - sizeof(struct ipv4_hdr));

		out_pkt->ol_flags |= PKT_TX_IP_CKSUM;
		out_pkt->l3_len = sizeof(struct ipv4_hdr);

		/* Write the fragment to the output list */
		pkts_out[out_pkt_pos] = out_pkt;
		out_pkt_pos ++;
	}

	return out_pkt_pos;
}