1 /* SPDX-License-Identifier: GPL-2.0 */ <<
2 /* 1 /*
3 * Definitions for the UDP-Lite (RFC 3828 2 * Definitions for the UDP-Lite (RFC 3828) code.
4 */ 3 */
5 #ifndef _UDPLITE_H 4 #ifndef _UDPLITE_H
6 #define _UDPLITE_H 5 #define _UDPLITE_H
7 6
8 #include <net/ip6_checksum.h> 7 #include <net/ip6_checksum.h>
9 #include <net/udp.h> <<
10 8
11 /* UDP-Lite socket options */ 9 /* UDP-Lite socket options */
12 #define UDPLITE_SEND_CSCOV 10 /* sender part 10 #define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
13 #define UDPLITE_RECV_CSCOV 11 /* receiver pa 11 #define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
14 12
15 extern struct proto udplite_prot; 13 extern struct proto udplite_prot;
16 extern struct udp_table udplite_table; 14 extern struct udp_table udplite_table;
17 15
18 /* 16 /*
19 * Checksum computation is all in softwar 17 * Checksum computation is all in software, hence simpler getfrag.
20 */ 18 */
21 static __inline__ int udplite_getfrag(void *fr 19 static __inline__ int udplite_getfrag(void *from, char *to, int offset,
22 int len, 20 int len, int odd, struct sk_buff *skb)
23 { 21 {
24 struct msghdr *msg = from; 22 struct msghdr *msg = from;
25 return copy_from_iter_full(to, len, &m 23 return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
26 } 24 }
27 25
>> 26 /* Designate sk as UDP-Lite socket */
>> 27 static inline int udplite_sk_init(struct sock *sk)
>> 28 {
>> 29 udp_sk(sk)->pcflag = UDPLITE_BIT;
>> 30 sk->sk_destruct = udp_destruct_sock;
>> 31 return 0;
>> 32 }
>> 33
28 /* 34 /*
29 * Checksumming routines 35 * Checksumming routines
30 */ 36 */
31 static inline int udplite_checksum_init(struct 37 static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
32 { 38 {
33 u16 cscov; 39 u16 cscov;
34 40
35 /* In UDPv4 a zero checksum means that 41 /* In UDPv4 a zero checksum means that the transmitter generated no
36 * checksum. UDP-Lite (like IPv6) mand 42 * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
37 * with a zero checksum field are ille 43 * with a zero checksum field are illegal. */
38 if (uh->check == 0) { 44 if (uh->check == 0) {
39 net_dbg_ratelimited("UDPLite: 45 net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
40 return 1; 46 return 1;
41 } 47 }
42 48
43 cscov = ntohs(uh->len); 49 cscov = ntohs(uh->len);
44 50
45 if (cscov == 0) /* Indicates 51 if (cscov == 0) /* Indicates that full coverage is required. */
46 ; 52 ;
47 else if (cscov < 8 || cscov > skb->le 53 else if (cscov < 8 || cscov > skb->len) {
48 /* 54 /*
49 * Coverage length violates RF 55 * Coverage length violates RFC 3828: log and discard silently.
50 */ 56 */
51 net_dbg_ratelimited("UDPLite: 57 net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
52 cscov, skb 58 cscov, skb->len);
53 return 1; 59 return 1;
54 60
55 } else if (cscov < skb->len) { 61 } else if (cscov < skb->len) {
56 UDP_SKB_CB(skb)->partial_cov = 62 UDP_SKB_CB(skb)->partial_cov = 1;
57 UDP_SKB_CB(skb)->cscov = cscov 63 UDP_SKB_CB(skb)->cscov = cscov;
58 if (skb->ip_summed == CHECKSUM 64 if (skb->ip_summed == CHECKSUM_COMPLETE)
59 skb->ip_summed = CHECK 65 skb->ip_summed = CHECKSUM_NONE;
60 skb->csum_valid = 0; <<
61 } 66 }
62 67
63 return 0; 68 return 0;
64 } 69 }
65 70
>> 71 /* Slow-path computation of checksum. Socket is locked. */
>> 72 static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
>> 73 {
>> 74 const struct udp_sock *up = udp_sk(skb->sk);
>> 75 int cscov = up->len;
>> 76 __wsum csum = 0;
>> 77
>> 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 */
>> 83 if (up->pcslen < up->len) {
>> 84 if (0 < up->pcslen)
>> 85 cscov = up->pcslen;
>> 86 udp_hdr(skb)->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
>> 100 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
>> 101
>> 102 skb_queue_walk(&sk->sk_write_queue, skb) {
>> 103 const int off = skb_transport_offset(skb);
>> 104 const int len = skb->len - off;
>> 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
66 /* Fast-path computation of checksum. Socket m 114 /* Fast-path computation of checksum. Socket may not be locked. */
67 static inline __wsum udplite_csum(struct sk_bu 115 static inline __wsum udplite_csum(struct sk_buff *skb)
68 { 116 {
>> 117 const struct udp_sock *up = udp_sk(skb->sk);
69 const int off = skb_transport_offset(s 118 const int off = skb_transport_offset(skb);
70 const struct sock *sk = skb->sk; <<
71 int len = skb->len - off; 119 int len = skb->len - off;
72 120
73 if (udp_test_bit(UDPLITE_SEND_CC, sk)) !! 121 if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
74 u16 pcslen = READ_ONCE(udp_sk( !! 122 if (0 < up->pcslen)
75 !! 123 len = up->pcslen;
76 if (pcslen < len) { !! 124 udp_hdr(skb)->len = htons(up->pcslen);
77 if (pcslen > 0) <<
78 len = pcslen; <<
79 udp_hdr(skb)->len = ht <<
80 } <<
81 } 125 }
82 skb->ip_summed = CHECKSUM_NONE; /* 126 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
83 127
84 return skb_checksum(skb, off, len, 0); 128 return skb_checksum(skb, off, len, 0);
85 } 129 }
86 130
87 void udplite4_register(void); 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 *));
88 #endif /* _UDPLITE_H */ 134 #endif /* _UDPLITE_H */
89 135
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