[RFC][PATCHv2 2.6.18-rc4-mm3 1/3] net/ipv4: UDP-Lite extensions
From: gerrit
Date: Mon Aug 28 2006 - 14:08:28 EST
[Net/IPv4]: REVISED UDP-Lite standalone support and shared UDP/-Lite socket structure.
This is in principle the same patch as posted earlier, with the difference that
all whitespace changes have been removed; in addition, statements have been re-ordered
so as to give a better-readable patch.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
include/linux/udp.h | 11 ++
include/net/udplite.h | 35 ++++++++
net/ipv4/udplite.c | 209 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 255 insertions(+)
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 90223f0..1b7cf10 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -50,12 +50,23 @@ struct udp_sock {
* when the socket is uncorked.
*/
__u16 len; /* total length of pending frames */
+ /*
+ * Fields specific to UDP-Lite.
+ */
+ __u16 pcslen;
+ __u16 pcrlen;
+/* indicator bits used by pcflag: */
+#define UDPLITE_BIT 0x1 /* set by udplite proto init function */
+#define UDPLITE_SEND_CC 0x2 /* set via udplite setsockopt */
+#define UDPLITE_RECV_CC 0x4 /* set via udplite setsocktopt */
+ __u8 pcflag; /* marks socket as UDP-Lite if > 0 */
};
static inline struct udp_sock *udp_sk(const struct sock *sk)
{
return (struct udp_sock *)sk;
}
+#define IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)
#endif
diff --git a/net/ipv4/udplite.c b/net/ipv4/udplite.c
new file mode 100644
index 0000000..3911403
--- /dev/null
+++ b/net/ipv4/udplite.c
@@ -0,0 +1,209 @@
+/*
+ * UDPLITE An implementation of the UDP-Lite protocol (RFC 3828).
+ *
+ * Version: $Id: udplite.c,v 1.22 2006/08/22 13:01:52 gerrit Exp gerrit $
+ *
+ * Authors: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
+ *
+ * Changes:
+ * Fixes:
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+struct hlist_head udplite_hash[UDP_HTABLE_SIZE];
+int udplite_port_rover;
+DEFINE_SNMP_STAT(struct udp_mib, udplite_statistics) __read_mostly;
+
+/* these functions are called by UDP-Lite with protocol-specific parameters */
+static int __udp_get_port(struct sock *, unsigned short,
+ struct hlist_head *, int * );
+static struct sock *__udp_lookup(u32 , u16, u32, u16, int, struct hlist_head *);
+static int __udp_mcast_deliver(struct sk_buff *, struct udphdr *,
+ u32, u32, struct hlist_head * );
+static int __udp_common_rcv(struct sk_buff *, int is_udplite);
+static void __udp_err(struct sk_buff *, u32, struct hlist_head *);
+#ifdef CONFIG_PROC_FS
+static int udp4_seq_show(struct seq_file *, void *);
+#endif
+
+/*
+ * Designate sk as UDP-Lite socket
+ */
+static inline int udplite_sk_init(struct sock *sk)
+{
+ udp_sk(sk)->pcflag = UDPLITE_BIT;
+ return 0;
+}
+
+static __inline__ int udplite_v4_get_port(struct sock *sk, unsigned short snum)
+{
+ return __udp_get_port(sk, snum, udplite_hash, &udplite_port_rover);
+}
+
+static __inline__ struct sock *udplite_v4_lookup(u32 saddr, u16 sport,
+ u32 daddr, u16 dport, int dif)
+{
+ return __udp_lookup(saddr, sport, daddr, dport, dif, udplite_hash);
+}
+
+static __inline__ int udplite_v4_mcast_deliver(struct sk_buff *skb,
+ struct udphdr *uh, u32 saddr, u32 daddr)
+{
+ return __udp_mcast_deliver(skb, uh, saddr, daddr, udplite_hash);
+}
+
+__inline__ int udplite_rcv(struct sk_buff *skb)
+{
+ return __udp_common_rcv(skb, 1);
+}
+
+__inline__ void udplite_err(struct sk_buff *skb, u32 info)
+{
+ return __udp_err(skb, info, udplite_hash);
+}
+
+static int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh,
+ unsigned short len, u32 saddr, u32 daddr)
+{
+ u16 cscov;
+
+ /* In UDPv4 a zero checksum means that the transmitter generated no
+ * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
+ * with a zero checksum field are illegal. */
+ if (uh->check == 0) {
+ LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: zeroed csum field"
+ "(%d.%d.%d.%d:%d -> %d.%d.%d.%d:%d)\n", NIPQUAD(saddr),
+ ntohs(uh->source), NIPQUAD(daddr), ntohs(uh->dest) );
+ return 0;
+ }
+
+ UDP_SKB_CB(skb)->partial_cov = 0;
+ cscov = ntohs(uh->len);
+
+ if (cscov == 0) /* Indicates that full coverage is required. */
+ cscov = len;
+ else if (cscov < 8 || cscov > len) {
+ /*
+ * Coverage length violates RFC 3828: log and discard silently.
+ */
+ LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: bad csum coverage %d/%d "
+ "(%d.%d.%d.%d:%d -> %d.%d.%d.%d:%d)\n", cscov, len,
+ NIPQUAD(saddr), ntohs(uh->source),
+ NIPQUAD(daddr), ntohs(uh->dest) );
+ return 0;
+
+ } else if (cscov < len)
+ UDP_SKB_CB(skb)->partial_cov = 1;
+
+ UDP_SKB_CB(skb)->cscov = cscov;
+
+ /*
+ * Initialise pseudo-header for checksum computation.
+ *
+ * There is no known NIC manufacturer supporting UDP-Lite yet,
+ * hence ip_summed is always (re-)set to CHECKSUM_NONE.
+ */
+ skb->csum = csum_tcpudp_nofold(saddr, daddr, len, IPPROTO_UDPLITE, 0);
+ skb->ip_summed = CHECKSUM_NONE;
+
+ return 1;
+}
+
+static void udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb,
+ int totlen, int cscov, u32 src, u32 dst)
+{
+ unsigned int csum = 0, len;
+ struct udphdr *uh = skb->h.uh;
+
+ uh->check = 0;
+
+ skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
+
+ if (skb_queue_len(&sk->sk_write_queue) == 1) {
+ /*
+ * Only one fragment on the socket.
+ */
+ csum = skb_checksum(skb, skb->h.raw - skb->data, cscov, 0);
+
+ } else {
+ skb_queue_walk(&sk->sk_write_queue, skb) {
+ len = skb->tail - skb->h.raw;
+
+ skb->csum = skb_checksum(skb, skb->h.raw - skb->data,
+ (cscov > len)? len : cscov, 0);
+ csum = csum_add(csum, skb->csum);
+
+ if (cscov < len) /* Enough seen. */
+ break;
+ cscov -= len;
+ }
+ }
+
+ uh->check = csum_tcpudp_magic(src, dst, totlen, IPPROTO_UDPLITE, csum);
+ if (uh->check == 0)
+ uh->check = -1;
+}
+
+
+static struct net_protocol udplite_protocol = {
+ .handler = udplite_rcv,
+ .err_handler = udplite_err,
+ .no_policy = 1,
+};
+
+static struct inet_protosw udplite4_protosw = {
+ .type = SOCK_DGRAM,
+ .protocol = IPPROTO_UDPLITE,
+ .prot = &udplite_prot,
+ .ops = &inet_dgram_ops,
+ .capability = -1,
+ .no_check = 0, /* must checksum (RFC 3828) */
+ .flags = INET_PROTOSW_PERMANENT,
+};
+
+void __init udplite4_register(void)
+{
+ if (proto_register(&udplite_prot, 1))
+ goto out_register_err;
+
+ if (inet_add_protocol(&udplite_protocol, IPPROTO_UDPLITE) < 0)
+ goto out_unregister_proto;
+
+ inet_register_protosw(&udplite4_protosw);
+
+ return;
+
+out_unregister_proto:
+ proto_unregister(&udplite_prot);
+out_register_err:
+ printk(KERN_CRIT "udplite4_register: Cannot add UDP-Lite protocol\n");
+}
+
+#ifdef CONFIG_PROC_FS
+static struct file_operations udplite4_seq_fops;
+static struct udp_seq_afinfo udplite4_seq_afinfo = {
+ .owner = THIS_MODULE,
+ .name = "udplite",
+ .family = AF_INET,
+ .hashtable = udplite_hash,
+ .seq_show = udp4_seq_show,
+ .seq_fops = &udplite4_seq_fops,
+};
+
+__inline__ int __init udplite4_proc_init(void)
+{
+ return udp_proc_register(&udplite4_seq_afinfo);
+}
+
+__inline__ void udplite4_proc_exit(void)
+{
+ udp_proc_unregister(&udplite4_seq_afinfo);
+}
+#endif /* CONFIG_PROC_FS */
+
+EXPORT_SYMBOL(udplite_hash);
+EXPORT_SYMBOL(udplite_prot);
diff --git a/include/net/udplite.h b/include/net/udplite.h
new file mode 100644
index 0000000..1a32c42
--- /dev/null
+++ b/include/net/udplite.h
@@ -0,0 +1,35 @@
+/*
+ * Definitions for the UDP-Lite (RFC 3828) code.
+ */
+#ifndef _UDPLITE_H
+#define _UDPLITE_H
+
+/* UDP-Lite socket options */
+#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
+#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
+
+extern struct proto udplite_prot;
+extern struct hlist_head udplite_hash[UDP_HTABLE_SIZE];
+
+/* UDP-Lite does not have a standardized MIB yet, so we inherit from UDP */
+DECLARE_SNMP_STAT(struct udp_mib, udplite_statistics);
+
+/*
+ * Checksum computation is all in software, hence simpler getfrag.
+ */
+static __inline__ int udplite_getfrag(void *from, char *to, int offset,
+ int len, int odd, struct sk_buff *skb)
+{
+ return memcpy_fromiovecend(to, (struct iovec *) from, offset, len);
+}
+
+/*
+ * net/ipv4/udplite.c
+ */
+extern void udplite4_register(void);
+#ifdef CONFIG_PROC_FS
+extern int udplite4_proc_init(void);
+extern void udplite4_proc_exit(void);
+#endif
+
+#endif /* _UDPLITE_H */
-
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