aboutsummaryrefslogtreecommitdiffstats
path: root/include/net/udplite.h
diff options
context:
space:
mode:
authorGerrit Renker <gerrit@erg.abdn.ac.uk>2006-11-27 11:10:57 -0800
committerDavid S. Miller <davem@sunset.davemloft.net>2006-12-02 21:22:46 -0800
commitba4e58eca8aa9473b44fdfd312f26c4a2e7798b3 (patch)
tree700f8f989f48da480beb83b983637cfd2b5a3f67 /include/net/udplite.h
parent6051e2f4fb68fc8e5343db58fa680ece376f405c (diff)
[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>
Diffstat (limited to 'include/net/udplite.h')
-rw-r--r--include/net/udplite.h149
1 files changed, 149 insertions, 0 deletions
diff --git a/include/net/udplite.h b/include/net/udplite.h
new file mode 100644
index 000000000000..1473b3e49044
--- /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 */

Privacy Policy