Bug Summary

File:net/eth.c
Location:line 210, column 9
Description:Value stored to 'bytes_read' is never read

Annotated Source Code

1/*
2 * QEMU network structures definitions and helper functions
3 *
4 * Copyright (c) 2012 Ravello Systems LTD (http://ravellosystems.com)
5 *
6 * Developed by Daynix Computing LTD (http://www.daynix.com)
7 *
8 * Authors:
9 * Dmitry Fleytman <dmitry@daynix.com>
10 * Tamir Shomer <tamirs@daynix.com>
11 * Yan Vugenfirer <yan@daynix.com>
12 *
13 * This work is licensed under the terms of the GNU GPL, version 2 or later.
14 * See the COPYING file in the top-level directory.
15 *
16 */
17
18#include "net/eth.h"
19#include "net/checksum.h"
20#include "qemu-common.h"
21#include "net/tap.h"
22
23void eth_setup_vlan_headers(struct eth_header *ehdr, uint16_t vlan_tag,
24 bool_Bool *is_new)
25{
26 struct vlan_header *vhdr = PKT_GET_VLAN_HDR(ehdr)((struct vlan_header *) (((uint8_t *)(ehdr)) + sizeof(struct eth_header
)));
27
28 switch (be16_to_cpu(ehdr->h_proto)) {
29 case ETH_P_VLAN(0x8100):
30 case ETH_P_DVLAN(0x88a8):
31 /* vlan hdr exists */
32 *is_new = false0;
33 break;
34
35 default:
36 /* No VLAN header, put a new one */
37 vhdr->h_proto = ehdr->h_proto;
38 ehdr->h_proto = cpu_to_be16(ETH_P_VLAN(0x8100));
39 *is_new = true1;
40 break;
41 }
42 vhdr->h_tci = cpu_to_be16(vlan_tag);
43}
44
45uint8_t
46eth_get_gso_type(uint16_t l3_proto, uint8_t *l3_hdr, uint8_t l4proto)
47{
48 uint8_t ecn_state = 0;
49
50 if (l3_proto == ETH_P_IP(0x0800)) {
51 struct ip_header *iphdr = (struct ip_header *) l3_hdr;
52
53 if (IP_HEADER_VERSION(iphdr)((iphdr->ip_ver_len >> 4)&0xf) == IP_HEADER_VERSION_4(4)) {
54 if (IPTOS_ECN(iphdr->ip_tos)((iphdr->ip_tos) & 0x03) == IPTOS_ECN_CE0x03) {
55 ecn_state = VIRTIO_NET_HDR_GSO_ECN0x80;
56 }
57 if (l4proto == IP_PROTO_TCP(6)) {
58 return VIRTIO_NET_HDR_GSO_TCPV41 | ecn_state;
59 } else if (l4proto == IP_PROTO_UDP(17)) {
60 return VIRTIO_NET_HDR_GSO_UDP3 | ecn_state;
61 }
62 }
63 } else if (l3_proto == ETH_P_IPV6(0x86dd)) {
64 struct ip6_header *ip6hdr = (struct ip6_header *) l3_hdr;
65
66 if (IP6_ECN(ip6hdr->ip6_ecn_acc)((ip6hdr->ip6_ctlun.ip6_un3.ip6_un3_ecn) & 0xC0) == IP6_ECN_CE0xC0) {
67 ecn_state = VIRTIO_NET_HDR_GSO_ECN0x80;
68 }
69
70 if (l4proto == IP_PROTO_TCP(6)) {
71 return VIRTIO_NET_HDR_GSO_TCPV64 | ecn_state;
72 }
73 }
74
75 /* Unsupported offload */
76 g_assert_not_reached()do { g_assertion_message (((gchar*) 0), "/home/stefan/src/qemu/qemu.org/qemu/net/eth.c"
, 76, ((const char*) (__PRETTY_FUNCTION__)), ((void*)0)); } while
(0);
77
78 return VIRTIO_NET_HDR_GSO_NONE0 | ecn_state;
79}
80
81void eth_get_protocols(const uint8_t *headers,
82 uint32_t hdr_length,
83 bool_Bool *isip4, bool_Bool *isip6,
84 bool_Bool *isudp, bool_Bool *istcp)
85{
86 int proto;
87 size_t l2hdr_len = eth_get_l2_hdr_length(headers);
88 assert(hdr_length >= eth_get_l2_hdr_length(headers))((hdr_length >= eth_get_l2_hdr_length(headers)) ? (void) (
0) : __assert_fail ("hdr_length >= eth_get_l2_hdr_length(headers)"
, "/home/stefan/src/qemu/qemu.org/qemu/net/eth.c", 88, __PRETTY_FUNCTION__
));
89 *isip4 = *isip6 = *isudp = *istcp = false0;
90
91 proto = eth_get_l3_proto(headers, l2hdr_len);
92 if (proto == ETH_P_IP(0x0800)) {
93 *isip4 = true1;
94
95 struct ip_header *iphdr;
96
97 assert(hdr_length >=((hdr_length >= eth_get_l2_hdr_length(headers) + sizeof(struct
ip_header)) ? (void) (0) : __assert_fail ("hdr_length >= eth_get_l2_hdr_length(headers) + sizeof(struct ip_header)"
, "/home/stefan/src/qemu/qemu.org/qemu/net/eth.c", 98, __PRETTY_FUNCTION__
))
98 eth_get_l2_hdr_length(headers) + sizeof(struct ip_header))((hdr_length >= eth_get_l2_hdr_length(headers) + sizeof(struct
ip_header)) ? (void) (0) : __assert_fail ("hdr_length >= eth_get_l2_hdr_length(headers) + sizeof(struct ip_header)"
, "/home/stefan/src/qemu/qemu.org/qemu/net/eth.c", 98, __PRETTY_FUNCTION__
));
99
100 iphdr = PKT_GET_IP_HDR(headers)((struct ip_header *)(((uint8_t *)(headers)) + eth_get_l2_hdr_length
(headers)));
101
102 if (IP_HEADER_VERSION(iphdr)((iphdr->ip_ver_len >> 4)&0xf) == IP_HEADER_VERSION_4(4)) {
103 if (iphdr->ip_p == IP_PROTO_TCP(6)) {
104 *istcp = true1;
105 } else if (iphdr->ip_p == IP_PROTO_UDP(17)) {
106 *isudp = true1;
107 }
108 }
109 } else if (proto == ETH_P_IPV6(0x86dd)) {
110 uint8_t l4proto;
111 size_t full_ip6hdr_len;
112
113 struct iovec hdr_vec;
114 hdr_vec.iov_base = (void *) headers;
115 hdr_vec.iov_len = hdr_length;
116
117 *isip6 = true1;
118 if (eth_parse_ipv6_hdr(&hdr_vec, 1, l2hdr_len,
119 &l4proto, &full_ip6hdr_len)) {
120 if (l4proto == IP_PROTO_TCP(6)) {
121 *istcp = true1;
122 } else if (l4proto == IP_PROTO_UDP(17)) {
123 *isudp = true1;
124 }
125 }
126 }
127}
128
129void
130eth_setup_ip4_fragmentation(const void *l2hdr, size_t l2hdr_len,
131 void *l3hdr, size_t l3hdr_len,
132 size_t l3payload_len,
133 size_t frag_offset, bool_Bool more_frags)
134{
135 if (eth_get_l3_proto(l2hdr, l2hdr_len) == ETH_P_IP(0x0800)) {
136 uint16_t orig_flags;
137 struct ip_header *iphdr = (struct ip_header *) l3hdr;
138 uint16_t frag_off_units = frag_offset / IP_FRAG_UNIT_SIZE(8);
139 uint16_t new_ip_off;
140
141 assert(frag_offset % IP_FRAG_UNIT_SIZE == 0)((frag_offset % (8) == 0) ? (void) (0) : __assert_fail ("frag_offset % (8) == 0"
, "/home/stefan/src/qemu/qemu.org/qemu/net/eth.c", 141, __PRETTY_FUNCTION__
));
142 assert((frag_off_units & ~IP_OFFMASK) == 0)(((frag_off_units & ~0x1fff) == 0) ? (void) (0) : __assert_fail
("(frag_off_units & ~0x1fff) == 0", "/home/stefan/src/qemu/qemu.org/qemu/net/eth.c"
, 142, __PRETTY_FUNCTION__));
143
144 orig_flags = be16_to_cpu(iphdr->ip_off) & ~(IP_OFFMASK0x1fff|IP_MF0x2000);
145 new_ip_off = frag_off_units | orig_flags | (more_frags ? IP_MF0x2000 : 0);
146 iphdr->ip_off = cpu_to_be16(new_ip_off);
147 iphdr->ip_len = cpu_to_be16(l3payload_len + l3hdr_len);
148 }
149}
150
151void
152eth_fix_ip4_checksum(void *l3hdr, size_t l3hdr_len)
153{
154 struct ip_header *iphdr = (struct ip_header *) l3hdr;
155 iphdr->ip_sum = 0;
156 iphdr->ip_sum = cpu_to_be16(net_raw_checksum(l3hdr, l3hdr_len));
157}
158
159uint32_t
160eth_calc_pseudo_hdr_csum(struct ip_header *iphdr, uint16_t csl)
161{
162 struct ip_pseudo_header ipph;
163 ipph.ip_src = iphdr->ip_src;
164 ipph.ip_dst = iphdr->ip_dst;
165 ipph.ip_payload = cpu_to_be16(csl);
166 ipph.ip_proto = iphdr->ip_p;
167 ipph.zeros = 0;
168 return net_checksum_add(sizeof(ipph), (uint8_t *) &ipph);
169}
170
171static bool_Bool
172eth_is_ip6_extension_header_type(uint8_t hdr_type)
173{
174 switch (hdr_type) {
175 case IP6_HOP_BY_HOP(0):
176 case IP6_ROUTING(43):
177 case IP6_FRAGMENT(44):
178 case IP6_ESP(50):
179 case IP6_AUTHENTICATION(51):
180 case IP6_DESTINATON(60):
181 case IP6_MOBILITY(135):
182 return true1;
183 default:
184 return false0;
185 }
186}
187
188bool_Bool eth_parse_ipv6_hdr(struct iovec *pkt, int pkt_frags,
189 size_t ip6hdr_off, uint8_t *l4proto,
190 size_t *full_hdr_len)
191{
192 struct ip6_header ip6_hdr;
193 struct ip6_ext_hdr ext_hdr;
194 size_t bytes_read;
195
196 bytes_read = iov_to_buf(pkt, pkt_frags, ip6hdr_off,
197 &ip6_hdr, sizeof(ip6_hdr));
198 if (bytes_read < sizeof(ip6_hdr)) {
199 return false0;
200 }
201
202 *full_hdr_len = sizeof(struct ip6_header);
203
204 if (!eth_is_ip6_extension_header_type(ip6_hdr.ip6_nxtip6_ctlun.ip6_un1.ip6_un1_nxt)) {
205 *l4proto = ip6_hdr.ip6_nxtip6_ctlun.ip6_un1.ip6_un1_nxt;
206 return true1;
207 }
208
209 do {
210 bytes_read = iov_to_buf(pkt, pkt_frags, ip6hdr_off + *full_hdr_len,
Value stored to 'bytes_read' is never read
211 &ext_hdr, sizeof(ext_hdr));
212 *full_hdr_len += (ext_hdr.ip6r_len + 1) * IP6_EXT_GRANULARITY(8);
213 } while (eth_is_ip6_extension_header_type(ext_hdr.ip6r_nxt));
214
215 *l4proto = ext_hdr.ip6r_nxt;
216 return true1;
217}