Commit | Line | Data |
---|---|---|
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 | ||
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 | { | |
22 | return memcpy_fromiovecend(to, (struct iovec *) from, offset, len); | |
23 | } | |
24 | ||
25 | /* Designate sk as UDP-Lite socket */ | |
26 | static inline int udplite_sk_init(struct sock *sk) | |
27 | { | |
28 | udp_sk(sk)->pcflag = UDPLITE_BIT; | |
29 | return 0; | |
30 | } | |
31 | ||
32 | /* | |
33 | * Checksumming routines | |
34 | */ | |
35 | static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh) | |
36 | { | |
37 | u16 cscov; | |
38 | ||
39 | /* In UDPv4 a zero checksum means that the transmitter generated no | |
40 | * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets | |
41 | * with a zero checksum field are illegal. */ | |
42 | if (uh->check == 0) { | |
43 | LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: zeroed checksum field\n"); | |
44 | return 1; | |
45 | } | |
46 | ||
ba4e58ec GR |
47 | cscov = ntohs(uh->len); |
48 | ||
49 | if (cscov == 0) /* Indicates that full coverage is required. */ | |
759e5d00 | 50 | ; |
ba4e58ec GR |
51 | else if (cscov < 8 || cscov > skb->len) { |
52 | /* | |
53 | * Coverage length violates RFC 3828: log and discard silently. | |
54 | */ | |
55 | LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: bad csum coverage %d/%d\n", | |
56 | cscov, skb->len); | |
57 | return 1; | |
58 | ||
759e5d00 | 59 | } else if (cscov < skb->len) { |
ba4e58ec | 60 | UDP_SKB_CB(skb)->partial_cov = 1; |
759e5d00 HX |
61 | UDP_SKB_CB(skb)->cscov = cscov; |
62 | if (skb->ip_summed == CHECKSUM_COMPLETE) | |
63 | skb->ip_summed = CHECKSUM_NONE; | |
64 | } | |
ba4e58ec GR |
65 | |
66 | return 0; | |
67 | } | |
68 | ||
ba4e58ec GR |
69 | static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh) |
70 | { | |
71 | int cscov = up->len; | |
72 | ||
73 | /* | |
74 | * Sender has set `partial coverage' option on UDP-Lite socket | |
75 | */ | |
76 | if (up->pcflag & UDPLITE_SEND_CC) { | |
77 | if (up->pcslen < up->len) { | |
78 | /* up->pcslen == 0 means that full coverage is required, | |
79 | * partial coverage only if 0 < up->pcslen < up->len */ | |
80 | if (0 < up->pcslen) { | |
81 | cscov = up->pcslen; | |
82 | } | |
83 | uh->len = htons(up->pcslen); | |
84 | } | |
85 | /* | |
86 | * NOTE: Causes for the error case `up->pcslen > up->len': | |
87 | * (i) Application error (will not be penalized). | |
88 | * (ii) Payload too big for send buffer: data is split | |
89 | * into several packets, each with its own header. | |
90 | * In this case (e.g. last segment), coverage may | |
91 | * exceed packet length. | |
92 | * Since packets with coverage length > packet length are | |
93 | * illegal, we fall back to the defaults here. | |
94 | */ | |
95 | } | |
96 | return cscov; | |
97 | } | |
98 | ||
868c86bc | 99 | static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) |
ba4e58ec | 100 | { |
4bedb452 | 101 | int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb)); |
868c86bc | 102 | __wsum csum = 0; |
ba4e58ec GR |
103 | |
104 | skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ | |
105 | ||
106 | skb_queue_walk(&sk->sk_write_queue, skb) { | |
ea2ae17d ACM |
107 | const int off = skb_transport_offset(skb); |
108 | const int len = skb->len - off; | |
ba4e58ec GR |
109 | |
110 | csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum); | |
111 | ||
112 | if ((cscov -= len) <= 0) | |
113 | break; | |
114 | } | |
115 | return csum; | |
116 | } | |
117 | ||
118 | extern void udplite4_register(void); | |
119 | extern int udplite_get_port(struct sock *sk, unsigned short snum, | |
df2bc459 | 120 | int (*scmp)(const struct sock *, const struct sock *)); |
ba4e58ec | 121 | #endif /* _UDPLITE_H */ |