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; | |
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 | { | |
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) { | |
afd46503 | 43 | LIMIT_NETDEBUG(KERN_DEBUG "UDPLite: zeroed checksum field\n"); |
ba4e58ec GR |
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 | */ | |
afd46503 | 55 | LIMIT_NETDEBUG(KERN_DEBUG "UDPLite: bad csum coverage %d/%d\n", |
ba4e58ec GR |
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 | ||
f36c23bb GR |
69 | /* Slow-path computation of checksum. Socket is locked. */ |
70 | static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb) | |
ba4e58ec | 71 | { |
f36c23bb | 72 | const struct udp_sock *up = udp_sk(skb->sk); |
ba4e58ec | 73 | int cscov = up->len; |
f36c23bb | 74 | __wsum csum = 0; |
ba4e58ec | 75 | |
f36c23bb GR |
76 | if (up->pcflag & UDPLITE_SEND_CC) { |
77 | /* | |
78 | * Sender has set `partial coverage' option on UDP-Lite socket. | |
79 | * The special case "up->pcslen == 0" signifies full coverage. | |
80 | */ | |
ba4e58ec | 81 | if (up->pcslen < up->len) { |
f36c23bb GR |
82 | if (0 < up->pcslen) |
83 | cscov = up->pcslen; | |
84 | udp_hdr(skb)->len = htons(up->pcslen); | |
ba4e58ec | 85 | } |
f36c23bb GR |
86 | /* |
87 | * NOTE: Causes for the error case `up->pcslen > up->len': | |
88 | * (i) Application error (will not be penalized). | |
89 | * (ii) Payload too big for send buffer: data is split | |
90 | * into several packets, each with its own header. | |
91 | * In this case (e.g. last segment), coverage may | |
92 | * exceed packet length. | |
93 | * Since packets with coverage length > packet length are | |
94 | * illegal, we fall back to the defaults here. | |
95 | */ | |
ba4e58ec | 96 | } |
ba4e58ec GR |
97 | |
98 | skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ | |
99 | ||
100 | skb_queue_walk(&sk->sk_write_queue, skb) { | |
ea2ae17d ACM |
101 | const int off = skb_transport_offset(skb); |
102 | const int len = skb->len - off; | |
ba4e58ec GR |
103 | |
104 | csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum); | |
105 | ||
106 | if ((cscov -= len) <= 0) | |
107 | break; | |
108 | } | |
109 | return csum; | |
110 | } | |
111 | ||
f36c23bb | 112 | /* Fast-path computation of checksum. Socket may not be locked. */ |
f6b9664f HX |
113 | static inline __wsum udplite_csum(struct sk_buff *skb) |
114 | { | |
f36c23bb | 115 | const struct udp_sock *up = udp_sk(skb->sk); |
f6b9664f | 116 | const int off = skb_transport_offset(skb); |
f36c23bb | 117 | int len = skb->len - off; |
f6b9664f | 118 | |
f36c23bb GR |
119 | if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) { |
120 | if (0 < up->pcslen) | |
121 | len = up->pcslen; | |
122 | udp_hdr(skb)->len = htons(up->pcslen); | |
123 | } | |
f6b9664f HX |
124 | skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */ |
125 | ||
f36c23bb | 126 | return skb_checksum(skb, off, len, 0); |
f6b9664f HX |
127 | } |
128 | ||
ba4e58ec GR |
129 | extern void udplite4_register(void); |
130 | extern int udplite_get_port(struct sock *sk, unsigned short snum, | |
df2bc459 | 131 | int (*scmp)(const struct sock *, const struct sock *)); |
ba4e58ec | 132 | #endif /* _UDPLITE_H */ |