svn commit: r271297 - head/sys/netinet
Adrian Chadd
adrian at FreeBSD.org
Tue Sep 9 03:10:22 UTC 2014
Author: adrian
Date: Tue Sep 9 03:10:21 2014
New Revision: 271297
URL: http://svnweb.freebsd.org/changeset/base/271297
Log:
Implement IPv4 RSS software hash functions to use during packet ingress
and egress.
* rss_mbuf_software_hash_v4 - look at the IPv4 mbuf to fetch the IPv4 details
+ direction to calculate a hash.
* rss_proto_software_hash_v4 - hash the given source/destination IPv4 address,
port and direction.
* rss_soft_m2cpuid - map the given mbuf to an RSS CPU ("bucket" for now)
These functions are intended to be used by the stack to support
the following:
* Not all NICs do RSS hashing, so we should support some way of doing
a hash in software;
* The NIC / driver may not hash frames the way we want (eg UDP 4-tuple
hashing when the stack is only doing 2-tuple hashing for UDP); so we
may need to re-hash frames;
* .. same with IPv4 fragments - they will need to be re-hashed after
reassembly;
* .. and same with things like IP tunneling and such;
* The transmit path for things like UDP, RAW and ICMP don't currently
have any RSS information attached to them - so they'll need an
RSS calculation performed before transmit.
TODO:
* Counters! Everywhere!
* Add a debug mode that software hashes received frames and compares them
to the hardware hash provided by the hardware to ensure they match.
The IPv6 part of this is missing - I'm going to do some re-juggling of
where various parts of the RSS framework live before I add the IPv6
code (read: the IPv6 code is going to go into netinet6/in6_rss.[ch],
rather than living here.)
Note: This API is still fluid. Please keep that in mind.
Differential Revision: https://reviews.freebsd.org/D527
Reviewed by: grehan
Modified:
head/sys/netinet/in_rss.c
head/sys/netinet/in_rss.h
Modified: head/sys/netinet/in_rss.c
==============================================================================
--- head/sys/netinet/in_rss.c Tue Sep 9 02:58:58 2014 (r271296)
+++ head/sys/netinet/in_rss.c Tue Sep 9 03:10:21 2014 (r271297)
@@ -57,6 +57,11 @@ __FBSDID("$FreeBSD$");
#include <netinet/in_var.h>
#include <netinet/toeplitz.h>
+/* for software rss hash support */
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
+
/*-
* Operating system parts of receiver-side scaling (RSS), which allows
* network cards to direct flows to particular receive queues based on hashes
@@ -170,6 +175,8 @@ struct rss_table_entry {
};
static struct rss_table_entry rss_table[RSS_TABLE_MAXLEN];
+static inline u_int rss_gethashconfig_local(void);
+
static void
rss_init(__unused void *arg)
{
@@ -491,6 +498,254 @@ rss_m2bucket(struct mbuf *m, uint32_t *b
}
/*
+ * Calculate an appropriate ipv4 2-tuple or 4-tuple given the given
+ * IPv4 source/destination address, UDP or TCP source/destination ports
+ * and the protocol type.
+ *
+ * The protocol code may wish to do a software hash of the given
+ * tuple. This depends upon the currently configured RSS hash types.
+ *
+ * This assumes that the packet in question isn't a fragment.
+ *
+ * It also assumes the packet source/destination address
+ * are in "incoming" packet order (ie, source is "far" address.)
+ */
+int
+rss_proto_software_hash_v4(struct in_addr s, struct in_addr d,
+ u_short sp, u_short dp, int proto,
+ uint32_t *hashval, uint32_t *hashtype)
+{
+ uint32_t hash;
+
+ /*
+ * Next, choose the hash type depending upon the protocol
+ * identifier.
+ */
+ if ((proto == IPPROTO_TCP) &&
+ (rss_gethashconfig_local() & RSS_HASHTYPE_RSS_TCP_IPV4)) {
+ hash = rss_hash_ip4_4tuple(s, sp, d, dp);
+ *hashval = hash;
+ *hashtype = M_HASHTYPE_RSS_TCP_IPV4;
+ return (0);
+ } else if ((proto == IPPROTO_UDP) &&
+ (rss_gethashconfig_local() & RSS_HASHTYPE_RSS_UDP_IPV4)) {
+ hash = rss_hash_ip4_4tuple(s, sp, d, dp);
+ *hashval = hash;
+ *hashtype = M_HASHTYPE_RSS_UDP_IPV4;
+ return (0);
+ } else if (rss_gethashconfig_local() & RSS_HASHTYPE_RSS_IPV4) {
+ /* RSS doesn't hash on other protocols like SCTP; so 2-tuple */
+ hash = rss_hash_ip4_2tuple(s, d);
+ *hashval = hash;
+ *hashtype = M_HASHTYPE_RSS_IPV4;
+ return (0);
+ }
+
+ /* No configured available hashtypes! */
+ printf("%s: no available hashtypes!\n", __func__);
+ return (-1);
+}
+
+/*
+ * Do a software calculation of the RSS for the given mbuf.
+ *
+ * This is typically used by the input path to recalculate the RSS after
+ * some form of packet processing (eg de-capsulation, IP fragment reassembly.)
+ *
+ * dir is the packet direction - RSS_HASH_PKT_INGRESS for incoming and
+ * RSS_HASH_PKT_EGRESS for outgoing.
+ *
+ * Returns 0 if a hash was done, -1 if no hash was done, +1 if
+ * the mbuf already had a valid RSS flowid.
+ *
+ * This function doesn't modify the mbuf. It's up to the caller to
+ * assign flowid/flowtype as appropriate.
+ */
+int
+rss_mbuf_software_hash_v4(const struct mbuf *m, int dir, uint32_t *hashval,
+ uint32_t *hashtype)
+{
+ const struct ip *ip;
+ const struct tcphdr *th;
+ const struct udphdr *uh;
+ uint8_t proto;
+ int iphlen;
+ int is_frag = 0;
+
+ /*
+ * XXX For now this only handles hashing on incoming mbufs.
+ */
+ if (dir != RSS_HASH_PKT_INGRESS) {
+ printf("%s: called on EGRESS packet!\n", __func__);
+ return (-1);
+ }
+
+ /*
+ * First, validate that the mbuf we have is long enough
+ * to have an IPv4 header in it.
+ */
+ if (m->m_pkthdr.len < (sizeof(struct ip))) {
+ printf("%s: short mbuf pkthdr\n", __func__);
+ return (-1);
+ }
+ if (m->m_len < (sizeof(struct ip))) {
+ printf("%s: short mbuf len\n", __func__);
+ return (-1);
+ }
+
+ /* Ok, let's dereference that */
+ ip = mtod(m, struct ip *);
+ proto = ip->ip_p;
+ iphlen = ip->ip_hl << 2;
+
+ /*
+ * If this is a fragment then it shouldn't be four-tuple
+ * hashed just yet. Once it's reassembled into a full
+ * frame it should be re-hashed.
+ */
+ if (ip->ip_off & htons(IP_MF | IP_OFFMASK))
+ is_frag = 1;
+
+ /*
+ * If the mbuf flowid/flowtype matches the packet type,
+ * and we don't support the 4-tuple version of the given protocol,
+ * then signal to the owner that it can trust the flowid/flowtype
+ * details.
+ *
+ * This is a little picky - eg, if TCPv4 / UDPv4 hashing
+ * is supported but we got a TCP/UDP frame only 2-tuple hashed,
+ * then we shouldn't just "trust" the 2-tuple hash. We need
+ * a 4-tuple hash.
+ */
+ if (m->m_flags & M_FLOWID) {
+ uint32_t flowid, flowtype;
+
+ flowid = m->m_pkthdr.flowid;
+ flowtype = M_HASHTYPE_GET(m);
+
+ switch (proto) {
+ case IPPROTO_UDP:
+ if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_UDP_IPV4) &&
+ (flowtype == M_HASHTYPE_RSS_UDP_IPV4) &&
+ (is_frag == 0)) {
+ return (1);
+ }
+ /*
+ * Only allow 2-tuple for UDP frames if we don't also
+ * support 4-tuple for UDP.
+ */
+ if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_IPV4) &&
+ ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_UDP_IPV4) == 0) &&
+ flowtype == M_HASHTYPE_RSS_IPV4) {
+ return (1);
+ }
+ break;
+ case IPPROTO_TCP:
+ if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_TCP_IPV4) &&
+ (flowtype == M_HASHTYPE_RSS_TCP_IPV4) &&
+ (is_frag == 0)) {
+ return (1);
+ }
+ /*
+ * Only allow 2-tuple for TCP frames if we don't also
+ * support 2-tuple for TCP.
+ */
+ if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_IPV4) &&
+ ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_TCP_IPV4) == 0) &&
+ flowtype == M_HASHTYPE_RSS_IPV4) {
+ return (1);
+ }
+ break;
+ default:
+ if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_IPV4) &&
+ flowtype == M_HASHTYPE_RSS_IPV4) {
+ return (1);
+ }
+ break;
+ }
+ }
+
+ /*
+ * Decode enough information to make a hash decision.
+ *
+ * XXX TODO: does the hardware hash on 4-tuple if IP
+ * options are present?
+ */
+ if (proto == IPPROTO_TCP && is_frag == 0) {
+ if (m->m_len < iphlen + sizeof(struct tcphdr)) {
+ printf("%s: short TCP frame?\n", __func__);
+ return (-1);
+ }
+ th = (struct tcphdr *)((caddr_t)ip + iphlen);
+ return rss_proto_software_hash_v4(ip->ip_src, ip->ip_dst,
+ th->th_sport,
+ th->th_dport,
+ proto,
+ hashval,
+ hashtype);
+ } else if (proto == IPPROTO_UDP && is_frag == 0) {
+ uh = (struct udphdr *)((caddr_t)ip + iphlen);
+ if (m->m_len < iphlen + sizeof(struct udphdr)) {
+ printf("%s: short UDP frame?\n", __func__);
+ return (-1);
+ }
+ return rss_proto_software_hash_v4(ip->ip_src, ip->ip_dst,
+ uh->uh_sport,
+ uh->uh_dport,
+ proto,
+ hashval,
+ hashtype);
+ } else {
+ /* Default to 2-tuple hash */
+ return rss_proto_software_hash_v4(ip->ip_src, ip->ip_dst,
+ 0, /* source port */
+ 0, /* destination port */
+ 0, /* IPPROTO_IP */
+ hashval,
+ hashtype);
+ }
+}
+
+/*
+ * Similar to rss_m2cpuid, but designed to be used by the IP NETISR
+ * on incoming frames.
+ *
+ * If an existing RSS hash exists and it matches what the configured
+ * hashing is, then use it.
+ *
+ * If there's an existing RSS hash but the desired hash is different,
+ * or if there's no useful RSS hash, then calculate it via
+ * the software path.
+ *
+ * XXX TODO: definitely want statistics here!
+ */
+struct mbuf *
+rss_soft_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid)
+{
+ uint32_t hash_val, hash_type;
+ int ret;
+
+ M_ASSERTPKTHDR(m);
+
+ ret = rss_mbuf_software_hash_v4(m, RSS_HASH_PKT_INGRESS,
+ &hash_val, &hash_type);
+ if (ret > 0) {
+ /* mbuf has a valid hash already; don't need to modify it */
+ *cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m));
+ } else if (ret == 0) {
+ /* hash was done; update */
+ m->m_pkthdr.flowid = hash_val;
+ M_HASHTYPE_SET(m, hash_type);
+ m->m_flags |= M_FLOWID;
+ *cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m));
+ } else { /* ret < 0 */
+ /* no hash was done */
+ *cpuid = NETISR_CPUID_NONE;
+ }
+ return (m);
+}
+
+/*
* Query the RSS hash algorithm.
*/
u_int
@@ -538,15 +793,10 @@ rss_getnumcpus(void)
return (rss_ncpus);
}
-/*
- * Return the supported RSS hash configuration.
- *
- * NICs should query this to determine what to configure in their redirection
- * matching table.
- */
-u_int
-rss_gethashconfig(void)
+static inline u_int
+rss_gethashconfig_local(void)
{
+
/* Return 4-tuple for TCP; 2-tuple for others */
/*
* UDP may fragment more often than TCP and thus we'll end up with
@@ -573,6 +823,19 @@ rss_gethashconfig(void)
}
/*
+ * Return the supported RSS hash configuration.
+ *
+ * NICs should query this to determine what to configure in their redirection
+ * matching table.
+ */
+u_int
+rss_gethashconfig(void)
+{
+
+ return (rss_gethashconfig_local());
+}
+
+/*
* XXXRW: Confirm that sysctl -a won't dump this keying material, don't want
* it appearing in debugging output unnecessarily.
*/
Modified: head/sys/netinet/in_rss.h
==============================================================================
--- head/sys/netinet/in_rss.h Tue Sep 9 02:58:58 2014 (r271296)
+++ head/sys/netinet/in_rss.h Tue Sep 9 03:10:21 2014 (r271297)
@@ -83,6 +83,16 @@
#define RSS_KEYSIZE 40
/*
+ * For RSS hash methods that do a software hash on an mbuf, the packet
+ * direction (ingress / egress) is required.
+ *
+ * The default direction (INGRESS) is the "receive into the NIC" - ie,
+ * what the hardware is hashing on.
+ */
+#define RSS_HASH_PKT_INGRESS 0
+#define RSS_HASH_PKT_EGRESS 1
+
+/*
* Device driver interfaces to query RSS properties that must be programmed
* into hardware.
*/
@@ -116,4 +126,17 @@ int rss_hash2bucket(uint32_t hash_val,
uint32_t *bucket_id);
int rss_m2bucket(struct mbuf *m, uint32_t *bucket_id);
+/*
+ * Functions to calculate a software RSS hash for a given mbuf or
+ * packet detail.
+ */
+int rss_mbuf_software_hash_v4(const struct mbuf *m, int dir,
+ uint32_t *hashval, uint32_t *hashtype);
+int rss_proto_software_hash_v4(struct in_addr src,
+ struct in_addr dst, u_short src_port, u_short dst_port,
+ int proto, uint32_t *hashval,
+ uint32_t *hashtype);
+struct mbuf * rss_soft_m2cpuid(struct mbuf *m, uintptr_t source,
+ u_int *cpuid);
+
#endif /* !_NETINET_IN_RSS_H_ */
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