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
This commit is contained in:
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Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=271297
@ -57,6 +57,11 @@ __FBSDID("$FreeBSD$");
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#include <netinet/in_var.h>
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#include <netinet/toeplitz.h>
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/* for software rss hash support */
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#include <netinet/ip.h>
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#include <netinet/tcp.h>
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#include <netinet/udp.h>
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/*-
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* Operating system parts of receiver-side scaling (RSS), which allows
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* network cards to direct flows to particular receive queues based on hashes
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@ -170,6 +175,8 @@ struct rss_table_entry {
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};
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static struct rss_table_entry rss_table[RSS_TABLE_MAXLEN];
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static inline u_int rss_gethashconfig_local(void);
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static void
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rss_init(__unused void *arg)
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{
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@ -490,6 +497,254 @@ rss_m2bucket(struct mbuf *m, uint32_t *bucket_id)
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bucket_id));
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}
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/*
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* Calculate an appropriate ipv4 2-tuple or 4-tuple given the given
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* IPv4 source/destination address, UDP or TCP source/destination ports
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* and the protocol type.
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*
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* The protocol code may wish to do a software hash of the given
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* tuple. This depends upon the currently configured RSS hash types.
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*
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* This assumes that the packet in question isn't a fragment.
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*
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* It also assumes the packet source/destination address
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* are in "incoming" packet order (ie, source is "far" address.)
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*/
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int
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rss_proto_software_hash_v4(struct in_addr s, struct in_addr d,
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u_short sp, u_short dp, int proto,
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uint32_t *hashval, uint32_t *hashtype)
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{
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uint32_t hash;
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/*
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* Next, choose the hash type depending upon the protocol
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* identifier.
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*/
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if ((proto == IPPROTO_TCP) &&
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(rss_gethashconfig_local() & RSS_HASHTYPE_RSS_TCP_IPV4)) {
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hash = rss_hash_ip4_4tuple(s, sp, d, dp);
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*hashval = hash;
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*hashtype = M_HASHTYPE_RSS_TCP_IPV4;
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return (0);
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} else if ((proto == IPPROTO_UDP) &&
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(rss_gethashconfig_local() & RSS_HASHTYPE_RSS_UDP_IPV4)) {
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hash = rss_hash_ip4_4tuple(s, sp, d, dp);
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*hashval = hash;
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*hashtype = M_HASHTYPE_RSS_UDP_IPV4;
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return (0);
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} else if (rss_gethashconfig_local() & RSS_HASHTYPE_RSS_IPV4) {
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/* RSS doesn't hash on other protocols like SCTP; so 2-tuple */
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hash = rss_hash_ip4_2tuple(s, d);
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*hashval = hash;
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*hashtype = M_HASHTYPE_RSS_IPV4;
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return (0);
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}
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/* No configured available hashtypes! */
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printf("%s: no available hashtypes!\n", __func__);
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return (-1);
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}
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/*
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* Do a software calculation of the RSS for the given mbuf.
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*
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* This is typically used by the input path to recalculate the RSS after
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* some form of packet processing (eg de-capsulation, IP fragment reassembly.)
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*
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* dir is the packet direction - RSS_HASH_PKT_INGRESS for incoming and
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* RSS_HASH_PKT_EGRESS for outgoing.
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*
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* Returns 0 if a hash was done, -1 if no hash was done, +1 if
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* the mbuf already had a valid RSS flowid.
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*
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* This function doesn't modify the mbuf. It's up to the caller to
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* assign flowid/flowtype as appropriate.
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*/
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int
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rss_mbuf_software_hash_v4(const struct mbuf *m, int dir, uint32_t *hashval,
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uint32_t *hashtype)
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{
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const struct ip *ip;
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const struct tcphdr *th;
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const struct udphdr *uh;
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uint8_t proto;
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int iphlen;
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int is_frag = 0;
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/*
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* XXX For now this only handles hashing on incoming mbufs.
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*/
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if (dir != RSS_HASH_PKT_INGRESS) {
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printf("%s: called on EGRESS packet!\n", __func__);
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return (-1);
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}
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/*
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* First, validate that the mbuf we have is long enough
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* to have an IPv4 header in it.
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*/
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if (m->m_pkthdr.len < (sizeof(struct ip))) {
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printf("%s: short mbuf pkthdr\n", __func__);
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return (-1);
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}
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if (m->m_len < (sizeof(struct ip))) {
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printf("%s: short mbuf len\n", __func__);
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return (-1);
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}
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/* Ok, let's dereference that */
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ip = mtod(m, struct ip *);
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proto = ip->ip_p;
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iphlen = ip->ip_hl << 2;
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/*
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* If this is a fragment then it shouldn't be four-tuple
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* hashed just yet. Once it's reassembled into a full
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* frame it should be re-hashed.
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*/
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if (ip->ip_off & htons(IP_MF | IP_OFFMASK))
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is_frag = 1;
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/*
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* If the mbuf flowid/flowtype matches the packet type,
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* and we don't support the 4-tuple version of the given protocol,
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* then signal to the owner that it can trust the flowid/flowtype
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* details.
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*
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* This is a little picky - eg, if TCPv4 / UDPv4 hashing
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* is supported but we got a TCP/UDP frame only 2-tuple hashed,
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* then we shouldn't just "trust" the 2-tuple hash. We need
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* a 4-tuple hash.
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*/
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if (m->m_flags & M_FLOWID) {
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uint32_t flowid, flowtype;
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flowid = m->m_pkthdr.flowid;
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flowtype = M_HASHTYPE_GET(m);
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switch (proto) {
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case IPPROTO_UDP:
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if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_UDP_IPV4) &&
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(flowtype == M_HASHTYPE_RSS_UDP_IPV4) &&
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(is_frag == 0)) {
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return (1);
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}
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/*
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* Only allow 2-tuple for UDP frames if we don't also
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* support 4-tuple for UDP.
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*/
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if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_IPV4) &&
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((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_UDP_IPV4) == 0) &&
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flowtype == M_HASHTYPE_RSS_IPV4) {
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return (1);
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}
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break;
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case IPPROTO_TCP:
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if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_TCP_IPV4) &&
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(flowtype == M_HASHTYPE_RSS_TCP_IPV4) &&
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(is_frag == 0)) {
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return (1);
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}
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/*
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* Only allow 2-tuple for TCP frames if we don't also
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* support 2-tuple for TCP.
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*/
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if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_IPV4) &&
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((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_TCP_IPV4) == 0) &&
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flowtype == M_HASHTYPE_RSS_IPV4) {
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return (1);
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}
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break;
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default:
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if ((rss_gethashconfig_local() & RSS_HASHTYPE_RSS_IPV4) &&
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flowtype == M_HASHTYPE_RSS_IPV4) {
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return (1);
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}
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break;
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}
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}
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/*
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* Decode enough information to make a hash decision.
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*
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* XXX TODO: does the hardware hash on 4-tuple if IP
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* options are present?
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*/
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if (proto == IPPROTO_TCP && is_frag == 0) {
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if (m->m_len < iphlen + sizeof(struct tcphdr)) {
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printf("%s: short TCP frame?\n", __func__);
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return (-1);
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}
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th = (struct tcphdr *)((caddr_t)ip + iphlen);
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return rss_proto_software_hash_v4(ip->ip_src, ip->ip_dst,
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th->th_sport,
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th->th_dport,
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proto,
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hashval,
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hashtype);
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} else if (proto == IPPROTO_UDP && is_frag == 0) {
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uh = (struct udphdr *)((caddr_t)ip + iphlen);
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if (m->m_len < iphlen + sizeof(struct udphdr)) {
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printf("%s: short UDP frame?\n", __func__);
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return (-1);
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}
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return rss_proto_software_hash_v4(ip->ip_src, ip->ip_dst,
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uh->uh_sport,
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uh->uh_dport,
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proto,
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hashval,
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hashtype);
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} else {
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/* Default to 2-tuple hash */
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return rss_proto_software_hash_v4(ip->ip_src, ip->ip_dst,
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0, /* source port */
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0, /* destination port */
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0, /* IPPROTO_IP */
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hashval,
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hashtype);
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}
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}
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/*
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* Similar to rss_m2cpuid, but designed to be used by the IP NETISR
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* on incoming frames.
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*
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* If an existing RSS hash exists and it matches what the configured
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* hashing is, then use it.
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*
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* If there's an existing RSS hash but the desired hash is different,
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* or if there's no useful RSS hash, then calculate it via
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* the software path.
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*
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* XXX TODO: definitely want statistics here!
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*/
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struct mbuf *
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rss_soft_m2cpuid(struct mbuf *m, uintptr_t source, u_int *cpuid)
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{
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uint32_t hash_val, hash_type;
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int ret;
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M_ASSERTPKTHDR(m);
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ret = rss_mbuf_software_hash_v4(m, RSS_HASH_PKT_INGRESS,
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&hash_val, &hash_type);
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if (ret > 0) {
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/* mbuf has a valid hash already; don't need to modify it */
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*cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m));
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} else if (ret == 0) {
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/* hash was done; update */
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m->m_pkthdr.flowid = hash_val;
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M_HASHTYPE_SET(m, hash_type);
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m->m_flags |= M_FLOWID;
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*cpuid = rss_hash2cpuid(m->m_pkthdr.flowid, M_HASHTYPE_GET(m));
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} else { /* ret < 0 */
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/* no hash was done */
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*cpuid = NETISR_CPUID_NONE;
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}
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return (m);
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}
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/*
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* Query the RSS hash algorithm.
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*/
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@ -538,15 +793,10 @@ rss_getnumcpus(void)
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return (rss_ncpus);
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}
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/*
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* Return the supported RSS hash configuration.
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*
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* NICs should query this to determine what to configure in their redirection
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* matching table.
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*/
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u_int
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rss_gethashconfig(void)
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static inline u_int
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rss_gethashconfig_local(void)
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{
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/* Return 4-tuple for TCP; 2-tuple for others */
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/*
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* UDP may fragment more often than TCP and thus we'll end up with
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@ -572,6 +822,19 @@ rss_gethashconfig(void)
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);
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}
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/*
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* Return the supported RSS hash configuration.
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*
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* NICs should query this to determine what to configure in their redirection
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* matching table.
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*/
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u_int
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rss_gethashconfig(void)
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{
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return (rss_gethashconfig_local());
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}
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/*
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* XXXRW: Confirm that sysctl -a won't dump this keying material, don't want
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* it appearing in debugging output unnecessarily.
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*/
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#define RSS_KEYSIZE 40
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/*
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* For RSS hash methods that do a software hash on an mbuf, the packet
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* direction (ingress / egress) is required.
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*
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* The default direction (INGRESS) is the "receive into the NIC" - ie,
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* what the hardware is hashing on.
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*/
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#define RSS_HASH_PKT_INGRESS 0
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#define RSS_HASH_PKT_EGRESS 1
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/*
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* Device driver interfaces to query RSS properties that must be programmed
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* into hardware.
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@ -116,4 +126,17 @@ int rss_hash2bucket(uint32_t hash_val, uint32_t hash_type,
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uint32_t *bucket_id);
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int rss_m2bucket(struct mbuf *m, uint32_t *bucket_id);
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/*
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* Functions to calculate a software RSS hash for a given mbuf or
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* packet detail.
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*/
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int rss_mbuf_software_hash_v4(const struct mbuf *m, int dir,
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uint32_t *hashval, uint32_t *hashtype);
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int rss_proto_software_hash_v4(struct in_addr src,
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struct in_addr dst, u_short src_port, u_short dst_port,
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int proto, uint32_t *hashval,
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uint32_t *hashtype);
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struct mbuf * rss_soft_m2cpuid(struct mbuf *m, uintptr_t source,
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u_int *cpuid);
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#endif /* !_NETINET_IN_RSS_H_ */
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