[NET]: Supporting UDP-Lite (RFC 3828) in Linux
This is a revision of the previously submitted patch, which alters
the way files are organized and compiled in the following manner:
* UDP and UDP-Lite now use separate object files
* source file dependencies resolved via header files
net/ipv{4,6}/udp_impl.h
* order of inclusion files in udp.c/udplite.c adapted
accordingly
[NET/IPv4]: Support for the UDP-Lite protocol (RFC 3828)
This patch adds support for UDP-Lite to the IPv4 stack, provided as an
extension to the existing UDPv4 code:
* generic routines are all located in net/ipv4/udp.c
* UDP-Lite specific routines are in net/ipv4/udplite.c
* MIB/statistics support in /proc/net/snmp and /proc/net/udplite
* shared API with extensions for partial checksum coverage
[NET/IPv6]: Extension for UDP-Lite over IPv6
It extends the existing UDPv6 code base with support for UDP-Lite
in the same manner as per UDPv4. In particular,
* UDPv6 generic and shared code is in net/ipv6/udp.c
* UDP-Litev6 specific extensions are in net/ipv6/udplite.c
* MIB/statistics support in /proc/net/snmp6 and /proc/net/udplite6
* support for IPV6_ADDRFORM
* aligned the coding style of protocol initialisation with af_inet6.c
* made the error handling in udpv6_queue_rcv_skb consistent;
to return `-1' on error on all error cases
* consolidation of shared code
[NET]: UDP-Lite Documentation and basic XFRM/Netfilter support
The UDP-Lite patch further provides
* API documentation for UDP-Lite
* basic xfrm support
* basic netfilter support for IPv4 and IPv6 (LOG target)
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/in.h b/include/linux/in.h
index 2619859..1912e7c 100644
--- a/include/linux/in.h
+++ b/include/linux/in.h
@@ -45,6 +45,7 @@
IPPROTO_COMP = 108, /* Compression Header protocol */
IPPROTO_SCTP = 132, /* Stream Control Transport Protocol */
+ IPPROTO_UDPLITE = 136, /* UDP-Lite (RFC 3828) */
IPPROTO_RAW = 255, /* Raw IP packets */
IPPROTO_MAX
diff --git a/include/linux/socket.h b/include/linux/socket.h
index 3614090..592b666 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -264,6 +264,7 @@
#define SOL_IPV6 41
#define SOL_ICMPV6 58
#define SOL_SCTP 132
+#define SOL_UDPLITE 136 /* UDP-Lite (RFC 3828) */
#define SOL_RAW 255
#define SOL_IPX 256
#define SOL_AX25 257
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 014b41d..564f3b0 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -38,6 +38,7 @@
#include <linux/types.h>
#include <net/inet_sock.h>
+#define UDP_HTABLE_SIZE 128
struct udp_sock {
/* inet_sock has to be the first member */
@@ -50,12 +51,23 @@
* 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/include/net/ipv6.h b/include/net/ipv6.h
index 3c266ad..9390649 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -158,9 +158,13 @@
SNMP_INC_STATS_OFFSET_BH(icmpv6_statistics, field, _offset); \
})
DECLARE_SNMP_STAT(struct udp_mib, udp_stats_in6);
-#define UDP6_INC_STATS(field) SNMP_INC_STATS(udp_stats_in6, field)
-#define UDP6_INC_STATS_BH(field) SNMP_INC_STATS_BH(udp_stats_in6, field)
-#define UDP6_INC_STATS_USER(field) SNMP_INC_STATS_USER(udp_stats_in6, field)
+DECLARE_SNMP_STAT(struct udp_mib, udplite_stats_in6);
+#define UDP6_INC_STATS_BH(field, is_udplite) do { \
+ if (is_udplite) SNMP_INC_STATS_BH(udplite_stats_in6, field); \
+ else SNMP_INC_STATS_BH(udp_stats_in6, field); } while(0)
+#define UDP6_INC_STATS_USER(field, is_udplite) do { \
+ if (is_udplite) SNMP_INC_STATS_USER(udplite_stats_in6, field); \
+ else SNMP_INC_STATS_USER(udp_stats_in6, field); } while(0)
int snmp6_register_dev(struct inet6_dev *idev);
int snmp6_unregister_dev(struct inet6_dev *idev);
@@ -604,6 +608,8 @@
extern void tcp6_proc_exit(void);
extern int udp6_proc_init(void);
extern void udp6_proc_exit(void);
+extern int udplite6_proc_init(void);
+extern void udplite6_proc_exit(void);
extern int ipv6_misc_proc_init(void);
extern void ipv6_misc_proc_exit(void);
diff --git a/include/net/transp_v6.h b/include/net/transp_v6.h
index 61f724c..409da3a 100644
--- a/include/net/transp_v6.h
+++ b/include/net/transp_v6.h
@@ -11,6 +11,7 @@
extern struct proto rawv6_prot;
extern struct proto udpv6_prot;
+extern struct proto udplitev6_prot;
extern struct proto tcpv6_prot;
struct flowi;
@@ -24,6 +25,7 @@
/* transport protocols */
extern void rawv6_init(void);
extern void udpv6_init(void);
+extern void udplitev6_init(void);
extern void tcpv6_init(void);
extern int udpv6_connect(struct sock *sk,
diff --git a/include/net/udp.h b/include/net/udp.h
index db0c05f..4f06267 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -26,9 +26,28 @@
#include <net/inet_sock.h>
#include <net/sock.h>
#include <net/snmp.h>
+#include <net/ip.h>
+#include <linux/ipv6.h>
#include <linux/seq_file.h>
-#define UDP_HTABLE_SIZE 128
+/**
+ * struct udp_skb_cb - UDP(-Lite) private variables
+ *
+ * @header: private variables used by IPv4/IPv6
+ * @cscov: checksum coverage length (UDP-Lite only)
+ * @partial_cov: if set indicates partial csum coverage
+ */
+struct udp_skb_cb {
+ union {
+ struct inet_skb_parm h4;
+#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
+ struct inet6_skb_parm h6;
+#endif
+ } header;
+ __u16 cscov;
+ __u8 partial_cov;
+};
+#define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))
extern struct hlist_head udp_hash[UDP_HTABLE_SIZE];
extern rwlock_t udp_hash_lock;
@@ -47,6 +66,62 @@
struct sk_buff;
+/*
+ * Generic checksumming routines for UDP(-Lite) v4 and v6
+ */
+static inline u16 __udp_lib_checksum_complete(struct sk_buff *skb)
+{
+ if (! UDP_SKB_CB(skb)->partial_cov)
+ return __skb_checksum_complete(skb);
+ return csum_fold(skb_checksum(skb, 0, UDP_SKB_CB(skb)->cscov,
+ skb->csum));
+}
+
+static __inline__ int udp_lib_checksum_complete(struct sk_buff *skb)
+{
+ return skb->ip_summed != CHECKSUM_UNNECESSARY &&
+ __udp_lib_checksum_complete(skb);
+}
+
+/**
+ * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
+ * @sk: socket we are writing to
+ * @skb: sk_buff containing the filled-in UDP header
+ * (checksum field must be zeroed out)
+ */
+static inline u32 udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
+{
+ u32 csum = csum_partial(skb->h.raw, sizeof(struct udphdr), 0);
+
+ skb_queue_walk(&sk->sk_write_queue, skb) {
+ csum = csum_add(csum, skb->csum);
+ }
+ return csum;
+}
+
+/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
+static inline void udp_lib_hash(struct sock *sk)
+{
+ BUG();
+}
+
+static inline void udp_lib_unhash(struct sock *sk)
+{
+ write_lock_bh(&udp_hash_lock);
+ if (sk_del_node_init(sk)) {
+ inet_sk(sk)->num = 0;
+ sock_prot_dec_use(sk->sk_prot);
+ }
+ write_unlock_bh(&udp_hash_lock);
+}
+
+static inline void udp_lib_close(struct sock *sk, long timeout)
+{
+ sk_common_release(sk);
+}
+
+
+/* net/ipv4/udp.c */
extern int udp_get_port(struct sock *sk, unsigned short snum,
int (*saddr_cmp)(const struct sock *, const struct sock *));
extern void udp_err(struct sk_buff *, u32);
@@ -61,21 +136,29 @@
poll_table *wait);
DECLARE_SNMP_STAT(struct udp_mib, udp_statistics);
-#define UDP_INC_STATS(field) SNMP_INC_STATS(udp_statistics, field)
-#define UDP_INC_STATS_BH(field) SNMP_INC_STATS_BH(udp_statistics, field)
-#define UDP_INC_STATS_USER(field) SNMP_INC_STATS_USER(udp_statistics, field)
+/*
+ * SNMP statistics for UDP and UDP-Lite
+ */
+#define UDP_INC_STATS_USER(field, is_udplite) do { \
+ if (is_udplite) SNMP_INC_STATS_USER(udplite_statistics, field); \
+ else SNMP_INC_STATS_USER(udp_statistics, field); } while(0)
+#define UDP_INC_STATS_BH(field, is_udplite) do { \
+ if (is_udplite) SNMP_INC_STATS_BH(udplite_statistics, field); \
+ else SNMP_INC_STATS_BH(udp_statistics, field); } while(0)
/* /proc */
struct udp_seq_afinfo {
struct module *owner;
char *name;
sa_family_t family;
+ struct hlist_head *hashtable;
int (*seq_show) (struct seq_file *m, void *v);
struct file_operations *seq_fops;
};
struct udp_iter_state {
sa_family_t family;
+ struct hlist_head *hashtable;
int bucket;
struct seq_operations seq_ops;
};
diff --git a/include/net/udplite.h b/include/net/udplite.h
new file mode 100644
index 0000000..1473b3e
--- /dev/null
+++ b/include/net/udplite.h
@@ -0,0 +1,149 @@
+/*
+ * 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);
+}
+
+/* Designate sk as UDP-Lite socket */
+static inline int udplite_sk_init(struct sock *sk)
+{
+ udp_sk(sk)->pcflag = UDPLITE_BIT;
+ return 0;
+}
+
+/*
+ * Checksumming routines
+ */
+static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
+{
+ 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 checksum field\n");
+ return 1;
+ }
+
+ UDP_SKB_CB(skb)->partial_cov = 0;
+ cscov = ntohs(uh->len);
+
+ if (cscov == 0) /* Indicates that full coverage is required. */
+ cscov = skb->len;
+ else if (cscov < 8 || cscov > skb->len) {
+ /*
+ * Coverage length violates RFC 3828: log and discard silently.
+ */
+ LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: bad csum coverage %d/%d\n",
+ cscov, skb->len);
+ return 1;
+
+ } else if (cscov < skb->len)
+ UDP_SKB_CB(skb)->partial_cov = 1;
+
+ UDP_SKB_CB(skb)->cscov = cscov;
+
+ /*
+ * There is no known NIC manufacturer supporting UDP-Lite yet,
+ * hence ip_summed is always (re-)set to CHECKSUM_NONE.
+ */
+ skb->ip_summed = CHECKSUM_NONE;
+
+ return 0;
+}
+
+static __inline__ int udplite4_csum_init(struct sk_buff *skb, struct udphdr *uh)
+{
+ int rc = udplite_checksum_init(skb, uh);
+
+ if (!rc)
+ skb->csum = csum_tcpudp_nofold(skb->nh.iph->saddr,
+ skb->nh.iph->daddr,
+ skb->len, IPPROTO_UDPLITE, 0);
+ return rc;
+}
+
+static __inline__ int udplite6_csum_init(struct sk_buff *skb, struct udphdr *uh)
+{
+ int rc = udplite_checksum_init(skb, uh);
+
+ if (!rc)
+ skb->csum = ~csum_ipv6_magic(&skb->nh.ipv6h->saddr,
+ &skb->nh.ipv6h->daddr,
+ skb->len, IPPROTO_UDPLITE, 0);
+ return rc;
+}
+
+static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh)
+{
+ int cscov = up->len;
+
+ /*
+ * Sender has set `partial coverage' option on UDP-Lite socket
+ */
+ if (up->pcflag & UDPLITE_SEND_CC) {
+ if (up->pcslen < up->len) {
+ /* up->pcslen == 0 means that full coverage is required,
+ * partial coverage only if 0 < up->pcslen < up->len */
+ if (0 < up->pcslen) {
+ cscov = up->pcslen;
+ }
+ uh->len = htons(up->pcslen);
+ }
+ /*
+ * NOTE: Causes for the error case `up->pcslen > up->len':
+ * (i) Application error (will not be penalized).
+ * (ii) Payload too big for send buffer: data is split
+ * into several packets, each with its own header.
+ * In this case (e.g. last segment), coverage may
+ * exceed packet length.
+ * Since packets with coverage length > packet length are
+ * illegal, we fall back to the defaults here.
+ */
+ }
+ return cscov;
+}
+
+static inline u32 udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
+{
+ u32 csum = 0;
+ int off, len, cscov = udplite_sender_cscov(udp_sk(sk), skb->h.uh);
+
+ skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
+
+ skb_queue_walk(&sk->sk_write_queue, skb) {
+ off = skb->h.raw - skb->data;
+ len = skb->len - off;
+
+ csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
+
+ if ((cscov -= len) <= 0)
+ break;
+ }
+ return csum;
+}
+
+extern void udplite4_register(void);
+extern int udplite_get_port(struct sock *sk, unsigned short snum,
+ int (*scmp)(const struct sock *, const struct sock *));
+#endif /* _UDPLITE_H */
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 81c91e8..3878a88 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -468,6 +468,7 @@
switch(fl->proto) {
case IPPROTO_TCP:
case IPPROTO_UDP:
+ case IPPROTO_UDPLITE:
case IPPROTO_SCTP:
port = fl->fl_ip_sport;
break;
@@ -493,6 +494,7 @@
switch(fl->proto) {
case IPPROTO_TCP:
case IPPROTO_UDP:
+ case IPPROTO_UDPLITE:
case IPPROTO_SCTP:
port = fl->fl_ip_dport;
break;