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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; | |
14 | extern struct hlist_head udplite_hash[UDP_HTABLE_SIZE]; | |
15 | ||
16 | /* UDP-Lite does not have a standardized MIB yet, so we inherit from UDP */ | |
17 | DECLARE_SNMP_STAT(struct udp_mib, udplite_statistics); | |
18 | ||
19 | /* | |
20 | * Checksum computation is all in software, hence simpler getfrag. | |
21 | */ | |
22 | static __inline__ int udplite_getfrag(void *from, char *to, int offset, | |
23 | int len, int odd, struct sk_buff *skb) | |
24 | { | |
25 | return memcpy_fromiovecend(to, (struct iovec *) from, offset, len); | |
26 | } | |
27 | ||
28 | /* Designate sk as UDP-Lite socket */ | |
29 | static inline int udplite_sk_init(struct sock *sk) | |
30 | { | |
31 | udp_sk(sk)->pcflag = UDPLITE_BIT; | |
32 | return 0; | |
33 | } | |
34 | ||
35 | /* | |
36 | * Checksumming routines | |
37 | */ | |
38 | static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh) | |
39 | { | |
40 | u16 cscov; | |
41 | ||
42 | /* In UDPv4 a zero checksum means that the transmitter generated no | |
43 | * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets | |
44 | * with a zero checksum field are illegal. */ | |
45 | if (uh->check == 0) { | |
46 | LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: zeroed checksum field\n"); | |
47 | return 1; | |
48 | } | |
49 | ||
ba4e58ec GR |
50 | cscov = ntohs(uh->len); |
51 | ||
52 | if (cscov == 0) /* Indicates that full coverage is required. */ | |
759e5d00 | 53 | ; |
ba4e58ec GR |
54 | else if (cscov < 8 || cscov > skb->len) { |
55 | /* | |
56 | * Coverage length violates RFC 3828: log and discard silently. | |
57 | */ | |
58 | LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: bad csum coverage %d/%d\n", | |
59 | cscov, skb->len); | |
60 | return 1; | |
61 | ||
759e5d00 | 62 | } else if (cscov < skb->len) { |
ba4e58ec | 63 | UDP_SKB_CB(skb)->partial_cov = 1; |
759e5d00 HX |
64 | UDP_SKB_CB(skb)->cscov = cscov; |
65 | if (skb->ip_summed == CHECKSUM_COMPLETE) | |
66 | skb->ip_summed = CHECKSUM_NONE; | |
67 | } | |
ba4e58ec GR |
68 | |
69 | return 0; | |
70 | } | |
71 | ||
ba4e58ec GR |
72 | static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh) |
73 | { | |
74 | int cscov = up->len; | |
75 | ||
76 | /* | |
77 | * Sender has set `partial coverage' option on UDP-Lite socket | |
78 | */ | |
79 | if (up->pcflag & UDPLITE_SEND_CC) { | |
80 | if (up->pcslen < up->len) { | |
81 | /* up->pcslen == 0 means that full coverage is required, | |
82 | * partial coverage only if 0 < up->pcslen < up->len */ | |
83 | if (0 < up->pcslen) { | |
84 | cscov = up->pcslen; | |
85 | } | |
86 | uh->len = htons(up->pcslen); | |
87 | } | |
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 | */ | |
98 | } | |
99 | return cscov; | |
100 | } | |
101 | ||
868c86bc | 102 | static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) |
ba4e58ec | 103 | { |
ba4e58ec | 104 | int off, len, cscov = udplite_sender_cscov(udp_sk(sk), skb->h.uh); |
868c86bc | 105 | __wsum csum = 0; |
ba4e58ec GR |
106 | |
107 | skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ | |
108 | ||
109 | skb_queue_walk(&sk->sk_write_queue, skb) { | |
110 | off = skb->h.raw - skb->data; | |
111 | len = skb->len - off; | |
112 | ||
113 | csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum); | |
114 | ||
115 | if ((cscov -= len) <= 0) | |
116 | break; | |
117 | } | |
118 | return csum; | |
119 | } | |
120 | ||
121 | extern void udplite4_register(void); | |
122 | extern int udplite_get_port(struct sock *sk, unsigned short snum, | |
123 | int (*scmp)(const struct sock *, const struct sock *)); | |
124 | #endif /* _UDPLITE_H */ |