Commit | Line | Data |
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ba4e58ec GR |
1 | /* |
2 | * Definitions for the UDP-Lite (RFC 3828) code. | |
3 | */ | |
4 | #ifndef _UDPLITE_H | |
5 | #define _UDPLITE_H | |
6 | ||
6bb100b9 DM |
7 | #include <net/ip6_checksum.h> |
8 | ||
ba4e58ec GR |
9 | /* UDP-Lite socket options */ |
10 | #define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */ | |
11 | #define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */ | |
12 | ||
13 | extern struct proto udplite_prot; | |
645ca708 | 14 | extern struct udp_table udplite_table; |
ba4e58ec | 15 | |
ba4e58ec GR |
16 | /* |
17 | * Checksum computation is all in software, hence simpler getfrag. | |
18 | */ | |
19 | static __inline__ int udplite_getfrag(void *from, char *to, int offset, | |
20 | int len, int odd, struct sk_buff *skb) | |
21 | { | |
f69e6d13 | 22 | struct msghdr *msg = from; |
0b62fca2 | 23 | return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT; |
ba4e58ec GR |
24 | } |
25 | ||
26 | /* Designate sk as UDP-Lite socket */ | |
27 | static inline int udplite_sk_init(struct sock *sk) | |
28 | { | |
2276f58a | 29 | udp_init_sock(sk); |
ba4e58ec GR |
30 | udp_sk(sk)->pcflag = UDPLITE_BIT; |
31 | return 0; | |
32 | } | |
33 | ||
34 | /* | |
35 | * Checksumming routines | |
36 | */ | |
37 | static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh) | |
38 | { | |
39 | u16 cscov; | |
40 | ||
41 | /* In UDPv4 a zero checksum means that the transmitter generated no | |
42 | * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets | |
43 | * with a zero checksum field are illegal. */ | |
44 | if (uh->check == 0) { | |
ba7a46f1 | 45 | net_dbg_ratelimited("UDPLite: zeroed checksum field\n"); |
ba4e58ec GR |
46 | return 1; |
47 | } | |
48 | ||
ba4e58ec GR |
49 | cscov = ntohs(uh->len); |
50 | ||
51 | if (cscov == 0) /* Indicates that full coverage is required. */ | |
759e5d00 | 52 | ; |
ba4e58ec GR |
53 | else if (cscov < 8 || cscov > skb->len) { |
54 | /* | |
55 | * Coverage length violates RFC 3828: log and discard silently. | |
56 | */ | |
ba7a46f1 JP |
57 | net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n", |
58 | cscov, skb->len); | |
ba4e58ec GR |
59 | return 1; |
60 | ||
759e5d00 | 61 | } else if (cscov < skb->len) { |
ba4e58ec | 62 | UDP_SKB_CB(skb)->partial_cov = 1; |
759e5d00 HX |
63 | UDP_SKB_CB(skb)->cscov = cscov; |
64 | if (skb->ip_summed == CHECKSUM_COMPLETE) | |
65 | skb->ip_summed = CHECKSUM_NONE; | |
66 | } | |
ba4e58ec GR |
67 | |
68 | return 0; | |
69 | } | |
70 | ||
f36c23bb GR |
71 | /* Slow-path computation of checksum. Socket is locked. */ |
72 | static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) | |
ba4e58ec | 73 | { |
f36c23bb | 74 | const struct udp_sock *up = udp_sk(skb->sk); |
ba4e58ec | 75 | int cscov = up->len; |
f36c23bb | 76 | __wsum csum = 0; |
ba4e58ec | 77 | |
f36c23bb GR |
78 | if (up->pcflag & UDPLITE_SEND_CC) { |
79 | /* | |
80 | * Sender has set `partial coverage' option on UDP-Lite socket. | |
81 | * The special case "up->pcslen == 0" signifies full coverage. | |
82 | */ | |
ba4e58ec | 83 | if (up->pcslen < up->len) { |
f36c23bb GR |
84 | if (0 < up->pcslen) |
85 | cscov = up->pcslen; | |
86 | udp_hdr(skb)->len = htons(up->pcslen); | |
ba4e58ec | 87 | } |
f36c23bb GR |
88 | /* |
89 | * NOTE: Causes for the error case `up->pcslen > up->len': | |
90 | * (i) Application error (will not be penalized). | |
91 | * (ii) Payload too big for send buffer: data is split | |
92 | * into several packets, each with its own header. | |
93 | * In this case (e.g. last segment), coverage may | |
94 | * exceed packet length. | |
95 | * Since packets with coverage length > packet length are | |
96 | * illegal, we fall back to the defaults here. | |
97 | */ | |
ba4e58ec | 98 | } |
ba4e58ec GR |
99 | |
100 | skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ | |
101 | ||
102 | skb_queue_walk(&sk->sk_write_queue, skb) { | |
ea2ae17d ACM |
103 | const int off = skb_transport_offset(skb); |
104 | const int len = skb->len - off; | |
ba4e58ec GR |
105 | |
106 | csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum); | |
107 | ||
108 | if ((cscov -= len) <= 0) | |
109 | break; | |
110 | } | |
111 | return csum; | |
112 | } | |
113 | ||
f36c23bb | 114 | /* Fast-path computation of checksum. Socket may not be locked. */ |
f6b9664f HX |
115 | static inline __wsum udplite_csum(struct sk_buff *skb) |
116 | { | |
f36c23bb | 117 | const struct udp_sock *up = udp_sk(skb->sk); |
f6b9664f | 118 | const int off = skb_transport_offset(skb); |
f36c23bb | 119 | int len = skb->len - off; |
f6b9664f | 120 | |
f36c23bb GR |
121 | if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) { |
122 | if (0 < up->pcslen) | |
123 | len = up->pcslen; | |
124 | udp_hdr(skb)->len = htons(up->pcslen); | |
125 | } | |
f6b9664f HX |
126 | skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ |
127 | ||
f36c23bb | 128 | return skb_checksum(skb, off, len, 0); |
f6b9664f HX |
129 | } |
130 | ||
16073439 JP |
131 | void udplite4_register(void); |
132 | int udplite_get_port(struct sock *sk, unsigned short snum, | |
133 | int (*scmp)(const struct sock *, const struct sock *)); | |
ba4e58ec | 134 | #endif /* _UDPLITE_H */ |