Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
  3  *              operating system.  INET is implemented using the  BSD Socket
  4  *              interface as the means of communication with the user level.
  5  *
  6  *              Definitions for the UDP module.
  7  *
  8  * Version:     @(#)udp.h       1.0.2   05/07/93
  9  *
 10  * Authors:     Ross Biro
 11  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 12  *
 13  * Fixes:
 14  *              Alan Cox        : Turned on udp checksums. I don't want to
 15  *                                chase 'memory corruption' bugs that aren't!
 16  *
 17  *              This program is free software; you can redistribute it and/or
 18  *              modify it under the terms of the GNU General Public License
 19  *              as published by the Free Software Foundation; either version
 20  *              2 of the License, or (at your option) any later version.
 21  */
 22 #ifndef _UDP_H
 23 #define _UDP_H
 24 
 25 #include <linux/list.h>
 26 #include <net/inet_sock.h>
 27 #include <net/sock.h>
 28 #include <net/snmp.h>
 29 #include <net/ip.h>
 30 #include <linux/ipv6.h>
 31 #include <linux/seq_file.h>
 32 #include <linux/poll.h>
 33 
 34 /**
 35  *      struct udp_skb_cb  -  UDP(-Lite) private variables
 36  *
 37  *      @header:      private variables used by IPv4/IPv6
 38  *      @cscov:       checksum coverage length (UDP-Lite only)
 39  *      @partial_cov: if set indicates partial csum coverage
 40  */
 41 struct udp_skb_cb {
 42         union {
 43                 struct inet_skb_parm    h4;
 44 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
 45                 struct inet6_skb_parm   h6;
 46 #endif
 47         } header;
 48         __u16           cscov;
 49         __u8            partial_cov;
 50 };
 51 #define UDP_SKB_CB(__skb)       ((struct udp_skb_cb *)((__skb)->cb))
 52 
 53 extern struct hlist_head udp_hash[UDP_HTABLE_SIZE];
 54 extern rwlock_t udp_hash_lock;
 55 
 56 
 57 /* Note: this must match 'valbool' in sock_setsockopt */
 58 #define UDP_CSUM_NOXMIT         1
 59 
 60 /* Used by SunRPC/xprt layer. */
 61 #define UDP_CSUM_NORCV          2
 62 
 63 /* Default, as per the RFC, is to always do csums. */
 64 #define UDP_CSUM_DEFAULT        0
 65 
 66 extern struct proto udp_prot;
 67 
 68 extern atomic_t udp_memory_allocated;
 69 
 70 /* sysctl variables for udp */
 71 extern int sysctl_udp_mem[3];
 72 extern int sysctl_udp_rmem_min;
 73 extern int sysctl_udp_wmem_min;
 74 
 75 struct sk_buff;
 76 
 77 /*
 78  *      Generic checksumming routines for UDP(-Lite) v4 and v6
 79  */
 80 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
 81 {
 82         return __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov);
 83 }
 84 
 85 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
 86 {
 87         return !skb_csum_unnecessary(skb) &&
 88                 __udp_lib_checksum_complete(skb);
 89 }
 90 
 91 /**
 92  *      udp_csum_outgoing  -  compute UDPv4/v6 checksum over fragments
 93  *      @sk:    socket we are writing to
 94  *      @skb:   sk_buff containing the filled-in UDP header
 95  *              (checksum field must be zeroed out)
 96  */
 97 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
 98 {
 99         __wsum csum = csum_partial(skb_transport_header(skb),
100                                    sizeof(struct udphdr), 0);
101         skb_queue_walk(&sk->sk_write_queue, skb) {
102                 csum = csum_add(csum, skb->csum);
103         }
104         return csum;
105 }
106 
107 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
108 static inline void udp_lib_hash(struct sock *sk)
109 {
110         BUG();
111 }
112 
113 static inline void udp_lib_unhash(struct sock *sk)
114 {
115         write_lock_bh(&udp_hash_lock);
116         if (sk_del_node_init(sk)) {
117                 inet_sk(sk)->num = 0;
118                 sock_prot_inuse_add(sk->sk_prot, -1);
119         }
120         write_unlock_bh(&udp_hash_lock);
121 }
122 
123 static inline void udp_lib_close(struct sock *sk, long timeout)
124 {
125         sk_common_release(sk);
126 }
127 
128 
129 /* net/ipv4/udp.c */
130 extern int      udp_get_port(struct sock *sk, unsigned short snum,
131                              int (*saddr_cmp)(const struct sock *, const struct sock *));
132 extern void     udp_err(struct sk_buff *, u32);
133 
134 extern int      udp_sendmsg(struct kiocb *iocb, struct sock *sk,
135                             struct msghdr *msg, size_t len);
136 
137 extern int      udp_rcv(struct sk_buff *skb);
138 extern int      udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
139 extern int      udp_disconnect(struct sock *sk, int flags);
140 extern unsigned int udp_poll(struct file *file, struct socket *sock,
141                              poll_table *wait);
142 extern int      udp_lib_getsockopt(struct sock *sk, int level, int optname,
143                                    char __user *optval, int __user *optlen);
144 extern int      udp_lib_setsockopt(struct sock *sk, int level, int optname,
145                                    char __user *optval, int optlen,
146                                    int (*push_pending_frames)(struct sock *));
147 
148 DECLARE_SNMP_STAT(struct udp_mib, udp_statistics);
149 DECLARE_SNMP_STAT(struct udp_mib, udp_stats_in6);
150 
151 /* UDP-Lite does not have a standardized MIB yet, so we inherit from UDP */
152 DECLARE_SNMP_STAT(struct udp_mib, udplite_statistics);
153 DECLARE_SNMP_STAT(struct udp_mib, udplite_stats_in6);
154 
155 /*
156  *      SNMP statistics for UDP and UDP-Lite
157  */
158 #define UDP_INC_STATS_USER(field, is_udplite)                          do {   \
159         if (is_udplite) SNMP_INC_STATS_USER(udplite_statistics, field);       \
160         else            SNMP_INC_STATS_USER(udp_statistics, field);  }  while(0)
161 #define UDP_INC_STATS_BH(field, is_udplite)                            do  {  \
162         if (is_udplite) SNMP_INC_STATS_BH(udplite_statistics, field);         \
163         else            SNMP_INC_STATS_BH(udp_statistics, field);    }  while(0)
164 
165 #define UDP6_INC_STATS_BH(field, is_udplite)                          do  {  \
166         if (is_udplite) SNMP_INC_STATS_BH(udplite_stats_in6, field);         \
167         else            SNMP_INC_STATS_BH(udp_stats_in6, field);    } while(0)
168 #define UDP6_INC_STATS_USER(field, is_udplite)                         do {    \
169         if (is_udplite) SNMP_INC_STATS_USER(udplite_stats_in6, field);         \
170         else            SNMP_INC_STATS_USER(udp_stats_in6, field);    } while(0)
171 
172 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
173 #define UDPX_INC_STATS_BH(sk, field) \
174         do { \
175                 if ((sk)->sk_family == AF_INET) \
176                         UDP_INC_STATS_BH(field, 0); \
177                 else \
178                         UDP6_INC_STATS_BH(field, 0); \
179         } while (0);
180 #else
181 #define UDPX_INC_STATS_BH(sk, field) UDP_INC_STATS_BH(field, 0)
182 #endif
183 
184 /* /proc */
185 struct udp_seq_afinfo {
186         struct module           *owner;
187         char                    *name;
188         sa_family_t             family;
189         struct hlist_head       *hashtable;
190         int                     (*seq_show) (struct seq_file *m, void *v);
191         struct file_operations  *seq_fops;
192 };
193 
194 struct udp_iter_state {
195         sa_family_t             family;
196         struct hlist_head       *hashtable;
197         int                     bucket;
198         struct seq_operations   seq_ops;
199 };
200 
201 #ifdef CONFIG_PROC_FS
202 extern int udp_proc_register(struct udp_seq_afinfo *afinfo);
203 extern void udp_proc_unregister(struct udp_seq_afinfo *afinfo);
204 
205 extern int  udp4_proc_init(void);
206 extern void udp4_proc_exit(void);
207 #endif
208 
209 extern void udp_init(void);
210 #endif  /* _UDP_H */
211 
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