1 /* SPDX-License-Identifier: GPL-2.0 */ 1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* 2 /*
3 * Definitions for the UDP-Lite (RFC 3828 3 * Definitions for the UDP-Lite (RFC 3828) code.
4 */ 4 */
5 #ifndef _UDPLITE_H 5 #ifndef _UDPLITE_H
6 #define _UDPLITE_H 6 #define _UDPLITE_H
7 7
8 #include <net/ip6_checksum.h> 8 #include <net/ip6_checksum.h>
9 #include <net/udp.h> <<
10 9
11 /* UDP-Lite socket options */ 10 /* UDP-Lite socket options */
12 #define UDPLITE_SEND_CSCOV 10 /* sender part 11 #define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
13 #define UDPLITE_RECV_CSCOV 11 /* receiver pa 12 #define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
14 13
15 extern struct proto udplite_prot; 14 extern struct proto udplite_prot;
16 extern struct udp_table udplite_table; 15 extern struct udp_table udplite_table;
17 16
18 /* 17 /*
19 * Checksum computation is all in softwar 18 * Checksum computation is all in software, hence simpler getfrag.
20 */ 19 */
21 static __inline__ int udplite_getfrag(void *fr 20 static __inline__ int udplite_getfrag(void *from, char *to, int offset,
22 int len, 21 int len, int odd, struct sk_buff *skb)
23 { 22 {
24 struct msghdr *msg = from; 23 struct msghdr *msg = from;
25 return copy_from_iter_full(to, len, &m 24 return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
26 } 25 }
27 26
>> 27 /* Designate sk as UDP-Lite socket */
>> 28 static inline int udplite_sk_init(struct sock *sk)
>> 29 {
>> 30 udp_init_sock(sk);
>> 31 udp_sk(sk)->pcflag = UDPLITE_BIT;
>> 32 return 0;
>> 33 }
>> 34
28 /* 35 /*
29 * Checksumming routines 36 * Checksumming routines
30 */ 37 */
31 static inline int udplite_checksum_init(struct 38 static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
32 { 39 {
33 u16 cscov; 40 u16 cscov;
34 41
35 /* In UDPv4 a zero checksum means that 42 /* In UDPv4 a zero checksum means that the transmitter generated no
36 * checksum. UDP-Lite (like IPv6) mand 43 * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
37 * with a zero checksum field are ille 44 * with a zero checksum field are illegal. */
38 if (uh->check == 0) { 45 if (uh->check == 0) {
39 net_dbg_ratelimited("UDPLite: 46 net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
40 return 1; 47 return 1;
41 } 48 }
42 49
43 cscov = ntohs(uh->len); 50 cscov = ntohs(uh->len);
44 51
45 if (cscov == 0) /* Indicates 52 if (cscov == 0) /* Indicates that full coverage is required. */
46 ; 53 ;
47 else if (cscov < 8 || cscov > skb->le 54 else if (cscov < 8 || cscov > skb->len) {
48 /* 55 /*
49 * Coverage length violates RF 56 * Coverage length violates RFC 3828: log and discard silently.
50 */ 57 */
51 net_dbg_ratelimited("UDPLite: 58 net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
52 cscov, skb 59 cscov, skb->len);
53 return 1; 60 return 1;
54 61
55 } else if (cscov < skb->len) { 62 } else if (cscov < skb->len) {
56 UDP_SKB_CB(skb)->partial_cov = 63 UDP_SKB_CB(skb)->partial_cov = 1;
57 UDP_SKB_CB(skb)->cscov = cscov 64 UDP_SKB_CB(skb)->cscov = cscov;
58 if (skb->ip_summed == CHECKSUM 65 if (skb->ip_summed == CHECKSUM_COMPLETE)
59 skb->ip_summed = CHECK 66 skb->ip_summed = CHECKSUM_NONE;
60 skb->csum_valid = 0; 67 skb->csum_valid = 0;
61 } 68 }
62 69
63 return 0; 70 return 0;
64 } 71 }
65 72
>> 73 /* Slow-path computation of checksum. Socket is locked. */
>> 74 static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
>> 75 {
>> 76 const struct udp_sock *up = udp_sk(skb->sk);
>> 77 int cscov = up->len;
>> 78 __wsum csum = 0;
>> 79
>> 80 if (up->pcflag & UDPLITE_SEND_CC) {
>> 81 /*
>> 82 * Sender has set `partial coverage' option on UDP-Lite socket.
>> 83 * The special case "up->pcslen == 0" signifies full coverage.
>> 84 */
>> 85 if (up->pcslen < up->len) {
>> 86 if (0 < up->pcslen)
>> 87 cscov = up->pcslen;
>> 88 udp_hdr(skb)->len = htons(up->pcslen);
>> 89 }
>> 90 /*
>> 91 * NOTE: Causes for the error case `up->pcslen > up->len':
>> 92 * (i) Application error (will not be penalized).
>> 93 * (ii) Payload too big for send buffer: data is split
>> 94 * into several packets, each with its own header.
>> 95 * In this case (e.g. last segment), coverage may
>> 96 * exceed packet length.
>> 97 * Since packets with coverage length > packet length are
>> 98 * illegal, we fall back to the defaults here.
>> 99 */
>> 100 }
>> 101
>> 102 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
>> 103
>> 104 skb_queue_walk(&sk->sk_write_queue, skb) {
>> 105 const int off = skb_transport_offset(skb);
>> 106 const int len = skb->len - off;
>> 107
>> 108 csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
>> 109
>> 110 if ((cscov -= len) <= 0)
>> 111 break;
>> 112 }
>> 113 return csum;
>> 114 }
>> 115
66 /* Fast-path computation of checksum. Socket m 116 /* Fast-path computation of checksum. Socket may not be locked. */
67 static inline __wsum udplite_csum(struct sk_bu 117 static inline __wsum udplite_csum(struct sk_buff *skb)
68 { 118 {
>> 119 const struct udp_sock *up = udp_sk(skb->sk);
69 const int off = skb_transport_offset(s 120 const int off = skb_transport_offset(skb);
70 const struct sock *sk = skb->sk; <<
71 int len = skb->len - off; 121 int len = skb->len - off;
72 122
73 if (udp_test_bit(UDPLITE_SEND_CC, sk)) !! 123 if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
74 u16 pcslen = READ_ONCE(udp_sk( !! 124 if (0 < up->pcslen)
75 !! 125 len = up->pcslen;
76 if (pcslen < len) { !! 126 udp_hdr(skb)->len = htons(up->pcslen);
77 if (pcslen > 0) <<
78 len = pcslen; <<
79 udp_hdr(skb)->len = ht <<
80 } <<
81 } 127 }
82 skb->ip_summed = CHECKSUM_NONE; /* 128 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
83 129
84 return skb_checksum(skb, off, len, 0); 130 return skb_checksum(skb, off, len, 0);
85 } 131 }
86 132
87 void udplite4_register(void); 133 void udplite4_register(void);
>> 134 int udplite_get_port(struct sock *sk, unsigned short snum,
>> 135 int (*scmp)(const struct sock *, const struct sock *));
88 #endif /* _UDPLITE_H */ 136 #endif /* _UDPLITE_H */
89 137
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