From a0f9f3c30390624d970cb08fed2de3d09d4fa2ec Mon Sep 17 00:00:00 2001 From: glebius Date: Fri, 10 Apr 2015 06:02:37 +0000 Subject: [PATCH] Move all code related to IP fragment reassembly to ip_reass.c. Some function names have changed and comments are reformatted or added, but there is no functional change. Claim copyright for me and Adrian. Sponsored by: Nginx, Inc. --- sys/conf/files | 1 + sys/netinet/in_var.h | 9 - sys/netinet/ip_input.c | 565 +---------------------------------- sys/netinet/ip_reass.c | 654 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 667 insertions(+), 562 deletions(-) create mode 100644 sys/netinet/ip_reass.c diff --git a/sys/conf/files b/sys/conf/files index 9e63ffe63dfe..7ef7afe64525 100644 --- a/sys/conf/files +++ b/sys/conf/files @@ -3485,6 +3485,7 @@ netinet/ip_ipsec.c optional inet ipsec netinet/ip_mroute.c optional mrouting inet netinet/ip_options.c optional inet netinet/ip_output.c optional inet +netinet/ip_reass.c optional inet netinet/raw_ip.c optional inet | inet6 netinet/cc/cc.c optional inet | inet6 netinet/cc/cc_newreno.c optional inet | inet6 diff --git a/sys/netinet/in_var.h b/sys/netinet/in_var.h index f7737ec1ee86..0318fb2ff9a2 100644 --- a/sys/netinet/in_var.h +++ b/sys/netinet/in_var.h @@ -175,15 +175,6 @@ do { \ IN_IFADDR_RUNLOCK(); \ } while (0) -/* - * IP datagram reassembly. - */ -#define IPREASS_NHASH_LOG2 6 -#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) -#define IPREASS_HMASK (IPREASS_NHASH - 1) -#define IPREASS_HASH(x,y) \ - (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) - /* * Legacy IPv4 IGMP per-link structure. */ diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c index e28fcc7ee9fa..1e139a231d82 100644 --- a/sys/netinet/ip_input.c +++ b/sys/netinet/ip_input.c @@ -89,6 +89,14 @@ __FBSDID("$FreeBSD$"); CTASSERT(sizeof(struct ip) == 20); #endif +/* IP reassembly functions are defined in ip_reass.c. */ +extern void ipreass_init(); +extern void ipreass_drain(); +extern void ipreass_slowtimo(); +#ifdef VIMAGE +extern void ipreass_destroy(); +#endif + struct rwlock in_ifaddr_lock; RW_SYSINIT(in_ifaddr_lock, &in_ifaddr_lock, "in_ifaddr_lock"); @@ -164,57 +172,6 @@ VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead); /* first inet address */ VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table */ VNET_DEFINE(u_long, in_ifaddrhmask); /* mask for hash table */ -static VNET_DEFINE(uma_zone_t, ipq_zone); -#define V_ipq_zone VNET(ipq_zone) -struct ipqbucket { - TAILQ_HEAD(ipqhead, ipq) head; - struct mtx lock; -}; -static VNET_DEFINE(struct ipqbucket, ipq[IPREASS_NHASH]); -#define V_ipq VNET(ipq) -static VNET_DEFINE(int, noreass); -#define V_noreass VNET(noreass) - -#define IPQ_LOCK(i) mtx_lock(&V_ipq[i].lock) -#define IPQ_TRYLOCK(i) mtx_trylock(&V_ipq[i].lock) -#define IPQ_UNLOCK(i) mtx_unlock(&V_ipq[i].lock) -#define IPQ_LOCK_ASSERT(i) mtx_assert(&V_ipq[i].lock, MA_OWNED) - -static int sysctl_maxfragpackets(SYSCTL_HANDLER_ARGS); -static void ipq_zone_change(void *); -static void ip_drain_vnet(void); -static void ipq_drain_tomax(void); -static void ipq_free(struct ipqhead *, struct ipq *); - -static inline void -ipq_timeout(struct ipqhead *head, struct ipq *fp) -{ - - IPSTAT_ADD(ips_fragtimeout, fp->ipq_nfrags); - ipq_free(head, fp); -} - -static inline void -ipq_drop(struct ipqhead *head, struct ipq *fp) -{ - - IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); - ipq_free(head, fp); -} - -SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_VNET | - CTLTYPE_INT | CTLFLAG_RW, NULL, 0, sysctl_maxfragpackets, "I", - "Maximum number of IPv4 fragment reassembly queue entries"); -SYSCTL_UMA_CUR(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_VNET, - &VNET_NAME(ipq_zone), - "Current number of IPv4 fragment reassembly queue entries"); - -static VNET_DEFINE(int, maxfragsperpacket); -#define V_maxfragsperpacket VNET(maxfragsperpacket) -SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_VNET | CTLFLAG_RW, - &VNET_NAME(maxfragsperpacket), 0, - "Maximum number of IPv4 fragments allowed per packet"); - #ifdef IPCTL_DEFMTU SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW, &ip_mtu, 0, "Default MTU"); @@ -349,15 +306,7 @@ ip_init(void) V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask); /* Initialize IP reassembly queue. */ - for (i = 0; i < IPREASS_NHASH; i++) { - TAILQ_INIT(&V_ipq[i].head); - mtx_init(&V_ipq[i].lock, "IP reassembly", NULL, - MTX_DEF | MTX_DUPOK); - } - V_maxfragsperpacket = 16; - V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, - NULL, UMA_ALIGN_PTR, 0); - uma_zone_set_max(V_ipq_zone, nmbclusters / 32); + ipreass_init(); /* Initialize packet filter hooks. */ V_inet_pfil_hook.ph_type = PFIL_TYPE_AF; @@ -390,9 +339,6 @@ ip_init(void) ip_protox[pr->pr_protocol] = pr - inetsw; } - EVENTHANDLER_REGISTER(nmbclusters_change, ipq_zone_change, - NULL, EVENTHANDLER_PRI_ANY); - netisr_register(&ip_nh); #ifdef RSS netisr_register(&ip_direct_nh); @@ -413,10 +359,7 @@ ip_destroy(void) hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask); /* Destroy IP reassembly queue. */ - ip_drain_vnet(); - uma_zdestroy(V_ipq_zone); - for (i = 0; i < IPREASS_NHASH; i++) - mtx_destroy(&V_ipq[i].lock); + ipreass_destroy(); } #endif @@ -809,466 +752,6 @@ ip_input(struct mbuf *m) m_freem(m); } -/* - * After maxnipq has been updated, propagate the change to UMA. The UMA zone - * max has slightly different semantics than the sysctl, for historical - * reasons. - */ -static void -ipq_drain_tomax(void) -{ - int target; - - /* - * If we are over the maximum number of fragments, - * drain off enough to get down to the new limit, - * stripping off last elements on queues. Every - * run we strip the oldest element from each bucket. - */ - target = uma_zone_get_max(V_ipq_zone); - while (uma_zone_get_cur(V_ipq_zone) > target) { - struct ipq *fp; - - for (int i = 0; i < IPREASS_NHASH; i++) { - IPQ_LOCK(i); - fp = TAILQ_LAST(&V_ipq[i].head, ipqhead); - if (fp != NULL) - ipq_timeout(&V_ipq[i].head, fp); - IPQ_UNLOCK(i); - } - } -} - -static void -ipq_zone_change(void *tag) -{ - - uma_zone_set_max(V_ipq_zone, nmbclusters / 32); - ipq_drain_tomax(); -} - -/* - * Change the limit on the UMA zone, or disable the fragment allocation - * at all. Since 0 and -1 is a special values here, we need our own handler, - * instead of sysctl_handle_uma_zone_max(). - */ -static int -sysctl_maxfragpackets(SYSCTL_HANDLER_ARGS) -{ - int error, max; - - if (V_noreass == 0) { - max = uma_zone_get_max(V_ipq_zone); - if (max == 0) - max = -1; - } else - max = 0; - error = sysctl_handle_int(oidp, &max, 0, req); - if (error || !req->newptr) - return (error); - if (max > 0) { - /* - * XXXRW: Might be a good idea to sanity check the argument - * and place an extreme upper bound. - */ - max = uma_zone_set_max(V_ipq_zone, max); - ipq_drain_tomax(); - V_noreass = 0; - } else if (max == 0) { - V_noreass = 1; - ip_drain_vnet(); - } else if (max == -1) { - V_noreass = 0; - uma_zone_set_max(V_ipq_zone, 0); - } else - return (EINVAL); - return (0); -} - -#define M_IP_FRAG M_PROTO9 - -/* - * Seek for old fragment queue header that can be reused. Try to - * reuse a header from currently locked hash bucket. - */ -static struct ipq * -ipq_reuse(int start) -{ - struct ipq *fp; - int i; - - IPQ_LOCK_ASSERT(start); - - for (i = start;; i++) { - if (i == IPREASS_NHASH) - i = 0; - if (i != start && IPQ_TRYLOCK(i) == 0) - continue; - fp = TAILQ_LAST(&V_ipq[i].head, ipqhead); - if (fp) { - struct mbuf *m; - - IPSTAT_ADD(ips_fragtimeout, fp->ipq_nfrags); - while (fp->ipq_frags) { - m = fp->ipq_frags; - fp->ipq_frags = m->m_nextpkt; - m_freem(m); - } - TAILQ_REMOVE(&V_ipq[i].head, fp, ipq_list); - if (i != start) - IPQ_UNLOCK(i); - IPQ_LOCK_ASSERT(start); - return (fp); - } - if (i != start) - IPQ_UNLOCK(i); - } -} - -/* - * Take incoming datagram fragment and try to reassemble it into - * whole datagram. If the argument is the first fragment or one - * in between the function will return NULL and store the mbuf - * in the fragment chain. If the argument is the last fragment - * the packet will be reassembled and the pointer to the new - * mbuf returned for further processing. Only m_tags attached - * to the first packet/fragment are preserved. - * The IP header is *NOT* adjusted out of iplen. - */ -struct mbuf * -ip_reass(struct mbuf *m) -{ - struct ip *ip; - struct mbuf *p, *q, *nq, *t; - struct ipq *fp; - struct ipqhead *head; - int i, hlen, next; - u_int8_t ecn, ecn0; - u_short hash; -#ifdef RSS - uint32_t rss_hash, rss_type; -#endif - - /* - * If no reassembling or maxfragsperpacket are 0, - * never accept fragments. - */ - if (V_noreass == 1 || V_maxfragsperpacket == 0) { - IPSTAT_INC(ips_fragments); - IPSTAT_INC(ips_fragdropped); - m_freem(m); - return (NULL); - } - - ip = mtod(m, struct ip *); - hlen = ip->ip_hl << 2; - - /* - * Adjust ip_len to not reflect header, - * convert offset of this to bytes. - */ - ip->ip_len = htons(ntohs(ip->ip_len) - hlen); - if (ip->ip_off & htons(IP_MF)) { - /* - * Make sure that fragments have a data length - * that's a non-zero multiple of 8 bytes. - */ - if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) { - IPSTAT_INC(ips_toosmall); /* XXX */ - IPSTAT_INC(ips_fragdropped); - m_freem(m); - return (NULL); - } - m->m_flags |= M_IP_FRAG; - } else - m->m_flags &= ~M_IP_FRAG; - ip->ip_off = htons(ntohs(ip->ip_off) << 3); - - /* - * Attempt reassembly; if it succeeds, proceed. - * ip_reass() will return a different mbuf. - */ - IPSTAT_INC(ips_fragments); - m->m_pkthdr.PH_loc.ptr = ip; - - /* - * Presence of header sizes in mbufs - * would confuse code below. - */ - m->m_data += hlen; - m->m_len -= hlen; - - hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); - head = &V_ipq[hash].head; - IPQ_LOCK(hash); - - /* - * Look for queue of fragments - * of this datagram. - */ - TAILQ_FOREACH(fp, head, ipq_list) - if (ip->ip_id == fp->ipq_id && - ip->ip_src.s_addr == fp->ipq_src.s_addr && - ip->ip_dst.s_addr == fp->ipq_dst.s_addr && -#ifdef MAC - mac_ipq_match(m, fp) && -#endif - ip->ip_p == fp->ipq_p) - break; - /* - * If first fragment to arrive, create a reassembly queue. - */ - if (fp == NULL) { - fp = uma_zalloc(V_ipq_zone, M_NOWAIT); - if (fp == NULL) - fp = ipq_reuse(hash); -#ifdef MAC - if (mac_ipq_init(fp, M_NOWAIT) != 0) { - uma_zfree(V_ipq_zone, fp); - fp = NULL; - goto dropfrag; - } - mac_ipq_create(m, fp); -#endif - TAILQ_INSERT_HEAD(head, fp, ipq_list); - fp->ipq_nfrags = 1; - fp->ipq_ttl = IPFRAGTTL; - fp->ipq_p = ip->ip_p; - fp->ipq_id = ip->ip_id; - fp->ipq_src = ip->ip_src; - fp->ipq_dst = ip->ip_dst; - fp->ipq_frags = m; - m->m_nextpkt = NULL; - goto done; - } else { - fp->ipq_nfrags++; -#ifdef MAC - mac_ipq_update(m, fp); -#endif - } - -#define GETIP(m) ((struct ip*)((m)->m_pkthdr.PH_loc.ptr)) - - /* - * Handle ECN by comparing this segment with the first one; - * if CE is set, do not lose CE. - * drop if CE and not-ECT are mixed for the same packet. - */ - ecn = ip->ip_tos & IPTOS_ECN_MASK; - ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; - if (ecn == IPTOS_ECN_CE) { - if (ecn0 == IPTOS_ECN_NOTECT) - goto dropfrag; - if (ecn0 != IPTOS_ECN_CE) - GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; - } - if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) - goto dropfrag; - - /* - * Find a segment which begins after this one does. - */ - for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) - if (ntohs(GETIP(q)->ip_off) > ntohs(ip->ip_off)) - break; - - /* - * If there is a preceding segment, it may provide some of - * our data already. If so, drop the data from the incoming - * segment. If it provides all of our data, drop us, otherwise - * stick new segment in the proper place. - * - * If some of the data is dropped from the preceding - * segment, then it's checksum is invalidated. - */ - if (p) { - i = ntohs(GETIP(p)->ip_off) + ntohs(GETIP(p)->ip_len) - - ntohs(ip->ip_off); - if (i > 0) { - if (i >= ntohs(ip->ip_len)) - goto dropfrag; - m_adj(m, i); - m->m_pkthdr.csum_flags = 0; - ip->ip_off = htons(ntohs(ip->ip_off) + i); - ip->ip_len = htons(ntohs(ip->ip_len) - i); - } - m->m_nextpkt = p->m_nextpkt; - p->m_nextpkt = m; - } else { - m->m_nextpkt = fp->ipq_frags; - fp->ipq_frags = m; - } - - /* - * While we overlap succeeding segments trim them or, - * if they are completely covered, dequeue them. - */ - for (; q != NULL && ntohs(ip->ip_off) + ntohs(ip->ip_len) > - ntohs(GETIP(q)->ip_off); q = nq) { - i = (ntohs(ip->ip_off) + ntohs(ip->ip_len)) - - ntohs(GETIP(q)->ip_off); - if (i < ntohs(GETIP(q)->ip_len)) { - GETIP(q)->ip_len = htons(ntohs(GETIP(q)->ip_len) - i); - GETIP(q)->ip_off = htons(ntohs(GETIP(q)->ip_off) + i); - m_adj(q, i); - q->m_pkthdr.csum_flags = 0; - break; - } - nq = q->m_nextpkt; - m->m_nextpkt = nq; - IPSTAT_INC(ips_fragdropped); - fp->ipq_nfrags--; - m_freem(q); - } - - /* - * Check for complete reassembly and perform frag per packet - * limiting. - * - * Frag limiting is performed here so that the nth frag has - * a chance to complete the packet before we drop the packet. - * As a result, n+1 frags are actually allowed per packet, but - * only n will ever be stored. (n = maxfragsperpacket.) - * - */ - next = 0; - for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { - if (ntohs(GETIP(q)->ip_off) != next) { - if (fp->ipq_nfrags > V_maxfragsperpacket) - ipq_drop(head, fp); - goto done; - } - next += ntohs(GETIP(q)->ip_len); - } - /* Make sure the last packet didn't have the IP_MF flag */ - if (p->m_flags & M_IP_FRAG) { - if (fp->ipq_nfrags > V_maxfragsperpacket) - ipq_drop(head, fp); - goto done; - } - - /* - * Reassembly is complete. Make sure the packet is a sane size. - */ - q = fp->ipq_frags; - ip = GETIP(q); - if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { - IPSTAT_INC(ips_toolong); - ipq_drop(head, fp); - goto done; - } - - /* - * Concatenate fragments. - */ - m = q; - t = m->m_next; - m->m_next = NULL; - m_cat(m, t); - nq = q->m_nextpkt; - q->m_nextpkt = NULL; - for (q = nq; q != NULL; q = nq) { - nq = q->m_nextpkt; - q->m_nextpkt = NULL; - m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; - m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; - m_cat(m, q); - } - /* - * In order to do checksumming faster we do 'end-around carry' here - * (and not in for{} loop), though it implies we are not going to - * reassemble more than 64k fragments. - */ - while (m->m_pkthdr.csum_data & 0xffff0000) - m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + - (m->m_pkthdr.csum_data >> 16); -#ifdef MAC - mac_ipq_reassemble(fp, m); - mac_ipq_destroy(fp); -#endif - - /* - * Create header for new ip packet by modifying header of first - * packet; dequeue and discard fragment reassembly header. - * Make header visible. - */ - ip->ip_len = htons((ip->ip_hl << 2) + next); - ip->ip_src = fp->ipq_src; - ip->ip_dst = fp->ipq_dst; - TAILQ_REMOVE(head, fp, ipq_list); - uma_zfree(V_ipq_zone, fp); - m->m_len += (ip->ip_hl << 2); - m->m_data -= (ip->ip_hl << 2); - /* some debugging cruft by sklower, below, will go away soon */ - if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ - m_fixhdr(m); - IPSTAT_INC(ips_reassembled); - IPQ_UNLOCK(hash); - -#ifdef RSS - /* - * Query the RSS layer for the flowid / flowtype for the - * mbuf payload. - * - * For now, just assume we have to calculate a new one. - * Later on we should check to see if the assigned flowid matches - * what RSS wants for the given IP protocol and if so, just keep it. - * - * We then queue into the relevant netisr so it can be dispatched - * to the correct CPU. - * - * Note - this may return 1, which means the flowid in the mbuf - * is correct for the configured RSS hash types and can be used. - */ - if (rss_mbuf_software_hash_v4(m, 0, &rss_hash, &rss_type) == 0) { - m->m_pkthdr.flowid = rss_hash; - M_HASHTYPE_SET(m, rss_type); - } - - /* - * Queue/dispatch for reprocessing. - * - * Note: this is much slower than just handling the frame in the - * current receive context. It's likely worth investigating - * why this is. - */ - netisr_dispatch(NETISR_IP_DIRECT, m); - return (NULL); -#endif - - /* Handle in-line */ - return (m); - -dropfrag: - IPSTAT_INC(ips_fragdropped); - if (fp != NULL) - fp->ipq_nfrags--; - m_freem(m); -done: - IPQ_UNLOCK(hash); - return (NULL); - -#undef GETIP -} - -/* - * Free a fragment reassembly header and all - * associated datagrams. - */ -static void -ipq_free(struct ipqhead *fhp, struct ipq *fp) -{ - struct mbuf *q; - - while (fp->ipq_frags) { - q = fp->ipq_frags; - fp->ipq_frags = q->m_nextpkt; - m_freem(q); - } - TAILQ_REMOVE(fhp, fp, ipq_list); - uma_zfree(V_ipq_zone, fp); -} - /* * IP timer processing; * if a timer expires on a reassembly @@ -1278,40 +761,16 @@ void ip_slowtimo(void) { VNET_ITERATOR_DECL(vnet_iter); - struct ipq *fp, *tmp; - int i; VNET_LIST_RLOCK_NOSLEEP(); VNET_FOREACH(vnet_iter) { CURVNET_SET(vnet_iter); - for (i = 0; i < IPREASS_NHASH; i++) { - IPQ_LOCK(i); - TAILQ_FOREACH_SAFE(fp, &V_ipq[i].head, ipq_list, tmp) - if (--fp->ipq_ttl == 0) - ipq_timeout(&V_ipq[i].head, fp); - IPQ_UNLOCK(i); - } + ipreass_slowtimo(); CURVNET_RESTORE(); } VNET_LIST_RUNLOCK_NOSLEEP(); } -/* - * Drain off all datagram fragments. - */ -static void -ip_drain_vnet(void) -{ - int i; - - for (i = 0; i < IPREASS_NHASH; i++) { - IPQ_LOCK(i); - while(!TAILQ_EMPTY(&V_ipq[i].head)) - ipq_drop(&V_ipq[i].head, TAILQ_FIRST(&V_ipq[i].head)); - IPQ_UNLOCK(i); - } -} - void ip_drain(void) { @@ -1320,7 +779,7 @@ ip_drain(void) VNET_LIST_RLOCK_NOSLEEP(); VNET_FOREACH(vnet_iter) { CURVNET_SET(vnet_iter); - ip_drain_vnet(); + ipreass_drain(); CURVNET_RESTORE(); } VNET_LIST_RUNLOCK_NOSLEEP(); diff --git a/sys/netinet/ip_reass.c b/sys/netinet/ip_reass.c new file mode 100644 index 000000000000..a7c5d38eb6d4 --- /dev/null +++ b/sys/netinet/ip_reass.c @@ -0,0 +1,654 @@ +/*- + * Copyright (c) 2015 Gleb Smirnoff + * Copyright (c) 2015 Adrian Chadd + * Copyright (c) 1982, 1986, 1988, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 + */ + +#include +__FBSDID("$FreeBSD$"); + +#include "opt_rss.h" + +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#include +#include +#include +#include +#ifdef MAC +#include +#endif + +SYSCTL_DECL(_net_inet_ip); + +/* + * Reassembly headers are stored in hash buckets. + */ +#define IPREASS_NHASH_LOG2 6 +#define IPREASS_NHASH (1 << IPREASS_NHASH_LOG2) +#define IPREASS_HMASK (IPREASS_NHASH - 1) +#define IPREASS_HASH(x,y) \ + (((((x) & 0xF) | ((((x) >> 8) & 0xF) << 4)) ^ (y)) & IPREASS_HMASK) + +struct ipqbucket { + TAILQ_HEAD(ipqhead, ipq) head; + struct mtx lock; +}; + +static VNET_DEFINE(struct ipqbucket, ipq[IPREASS_NHASH]); +#define V_ipq VNET(ipq) + +#define IPQ_LOCK(i) mtx_lock(&V_ipq[i].lock) +#define IPQ_TRYLOCK(i) mtx_trylock(&V_ipq[i].lock) +#define IPQ_UNLOCK(i) mtx_unlock(&V_ipq[i].lock) +#define IPQ_LOCK_ASSERT(i) mtx_assert(&V_ipq[i].lock, MA_OWNED) + +void ipreass_init(void); +void ipreass_drain(void); +void ipreass_slowtimo(void); +#ifdef VIMAGE +void ipreass_destroy(void); +#endif +static int sysctl_maxfragpackets(SYSCTL_HANDLER_ARGS); +static void ipreass_zone_change(void *); +static void ipreass_drain_tomax(void); +static void ipq_free(struct ipqhead *, struct ipq *); +static struct ipq * ipq_reuse(int); + +static inline void +ipq_timeout(struct ipqhead *head, struct ipq *fp) +{ + + IPSTAT_ADD(ips_fragtimeout, fp->ipq_nfrags); + ipq_free(head, fp); +} + +static inline void +ipq_drop(struct ipqhead *head, struct ipq *fp) +{ + + IPSTAT_ADD(ips_fragdropped, fp->ipq_nfrags); + ipq_free(head, fp); +} + +static VNET_DEFINE(uma_zone_t, ipq_zone); +#define V_ipq_zone VNET(ipq_zone) +SYSCTL_PROC(_net_inet_ip, OID_AUTO, maxfragpackets, CTLFLAG_VNET | + CTLTYPE_INT | CTLFLAG_RW, NULL, 0, sysctl_maxfragpackets, "I", + "Maximum number of IPv4 fragment reassembly queue entries"); +SYSCTL_UMA_CUR(_net_inet_ip, OID_AUTO, fragpackets, CTLFLAG_VNET, + &VNET_NAME(ipq_zone), + "Current number of IPv4 fragment reassembly queue entries"); + +static VNET_DEFINE(int, noreass); +#define V_noreass VNET(noreass) + +static VNET_DEFINE(int, maxfragsperpacket); +#define V_maxfragsperpacket VNET(maxfragsperpacket) +SYSCTL_INT(_net_inet_ip, OID_AUTO, maxfragsperpacket, CTLFLAG_VNET | CTLFLAG_RW, + &VNET_NAME(maxfragsperpacket), 0, + "Maximum number of IPv4 fragments allowed per packet"); + +/* + * Take incoming datagram fragment and try to reassemble it into + * whole datagram. If the argument is the first fragment or one + * in between the function will return NULL and store the mbuf + * in the fragment chain. If the argument is the last fragment + * the packet will be reassembled and the pointer to the new + * mbuf returned for further processing. Only m_tags attached + * to the first packet/fragment are preserved. + * The IP header is *NOT* adjusted out of iplen. + */ +#define M_IP_FRAG M_PROTO9 +struct mbuf * +ip_reass(struct mbuf *m) +{ + struct ip *ip; + struct mbuf *p, *q, *nq, *t; + struct ipq *fp; + struct ipqhead *head; + int i, hlen, next; + u_int8_t ecn, ecn0; + u_short hash; +#ifdef RSS + uint32_t rss_hash, rss_type; +#endif + + /* + * If no reassembling or maxfragsperpacket are 0, + * never accept fragments. + */ + if (V_noreass == 1 || V_maxfragsperpacket == 0) { + IPSTAT_INC(ips_fragments); + IPSTAT_INC(ips_fragdropped); + m_freem(m); + return (NULL); + } + + ip = mtod(m, struct ip *); + hlen = ip->ip_hl << 2; + + /* + * Adjust ip_len to not reflect header, + * convert offset of this to bytes. + */ + ip->ip_len = htons(ntohs(ip->ip_len) - hlen); + if (ip->ip_off & htons(IP_MF)) { + /* + * Make sure that fragments have a data length + * that's a non-zero multiple of 8 bytes. + */ + if (ip->ip_len == htons(0) || (ntohs(ip->ip_len) & 0x7) != 0) { + IPSTAT_INC(ips_toosmall); /* XXX */ + IPSTAT_INC(ips_fragdropped); + m_freem(m); + return (NULL); + } + m->m_flags |= M_IP_FRAG; + } else + m->m_flags &= ~M_IP_FRAG; + ip->ip_off = htons(ntohs(ip->ip_off) << 3); + + /* + * Attempt reassembly; if it succeeds, proceed. + * ip_reass() will return a different mbuf. + */ + IPSTAT_INC(ips_fragments); + m->m_pkthdr.PH_loc.ptr = ip; + + /* + * Presence of header sizes in mbufs + * would confuse code below. + */ + m->m_data += hlen; + m->m_len -= hlen; + + hash = IPREASS_HASH(ip->ip_src.s_addr, ip->ip_id); + head = &V_ipq[hash].head; + IPQ_LOCK(hash); + + /* + * Look for queue of fragments + * of this datagram. + */ + TAILQ_FOREACH(fp, head, ipq_list) + if (ip->ip_id == fp->ipq_id && + ip->ip_src.s_addr == fp->ipq_src.s_addr && + ip->ip_dst.s_addr == fp->ipq_dst.s_addr && +#ifdef MAC + mac_ipq_match(m, fp) && +#endif + ip->ip_p == fp->ipq_p) + break; + /* + * If first fragment to arrive, create a reassembly queue. + */ + if (fp == NULL) { + fp = uma_zalloc(V_ipq_zone, M_NOWAIT); + if (fp == NULL) + fp = ipq_reuse(hash); +#ifdef MAC + if (mac_ipq_init(fp, M_NOWAIT) != 0) { + uma_zfree(V_ipq_zone, fp); + fp = NULL; + goto dropfrag; + } + mac_ipq_create(m, fp); +#endif + TAILQ_INSERT_HEAD(head, fp, ipq_list); + fp->ipq_nfrags = 1; + fp->ipq_ttl = IPFRAGTTL; + fp->ipq_p = ip->ip_p; + fp->ipq_id = ip->ip_id; + fp->ipq_src = ip->ip_src; + fp->ipq_dst = ip->ip_dst; + fp->ipq_frags = m; + m->m_nextpkt = NULL; + goto done; + } else { + fp->ipq_nfrags++; +#ifdef MAC + mac_ipq_update(m, fp); +#endif + } + +#define GETIP(m) ((struct ip*)((m)->m_pkthdr.PH_loc.ptr)) + + /* + * Handle ECN by comparing this segment with the first one; + * if CE is set, do not lose CE. + * drop if CE and not-ECT are mixed for the same packet. + */ + ecn = ip->ip_tos & IPTOS_ECN_MASK; + ecn0 = GETIP(fp->ipq_frags)->ip_tos & IPTOS_ECN_MASK; + if (ecn == IPTOS_ECN_CE) { + if (ecn0 == IPTOS_ECN_NOTECT) + goto dropfrag; + if (ecn0 != IPTOS_ECN_CE) + GETIP(fp->ipq_frags)->ip_tos |= IPTOS_ECN_CE; + } + if (ecn == IPTOS_ECN_NOTECT && ecn0 != IPTOS_ECN_NOTECT) + goto dropfrag; + + /* + * Find a segment which begins after this one does. + */ + for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) + if (ntohs(GETIP(q)->ip_off) > ntohs(ip->ip_off)) + break; + + /* + * If there is a preceding segment, it may provide some of + * our data already. If so, drop the data from the incoming + * segment. If it provides all of our data, drop us, otherwise + * stick new segment in the proper place. + * + * If some of the data is dropped from the preceding + * segment, then it's checksum is invalidated. + */ + if (p) { + i = ntohs(GETIP(p)->ip_off) + ntohs(GETIP(p)->ip_len) - + ntohs(ip->ip_off); + if (i > 0) { + if (i >= ntohs(ip->ip_len)) + goto dropfrag; + m_adj(m, i); + m->m_pkthdr.csum_flags = 0; + ip->ip_off = htons(ntohs(ip->ip_off) + i); + ip->ip_len = htons(ntohs(ip->ip_len) - i); + } + m->m_nextpkt = p->m_nextpkt; + p->m_nextpkt = m; + } else { + m->m_nextpkt = fp->ipq_frags; + fp->ipq_frags = m; + } + + /* + * While we overlap succeeding segments trim them or, + * if they are completely covered, dequeue them. + */ + for (; q != NULL && ntohs(ip->ip_off) + ntohs(ip->ip_len) > + ntohs(GETIP(q)->ip_off); q = nq) { + i = (ntohs(ip->ip_off) + ntohs(ip->ip_len)) - + ntohs(GETIP(q)->ip_off); + if (i < ntohs(GETIP(q)->ip_len)) { + GETIP(q)->ip_len = htons(ntohs(GETIP(q)->ip_len) - i); + GETIP(q)->ip_off = htons(ntohs(GETIP(q)->ip_off) + i); + m_adj(q, i); + q->m_pkthdr.csum_flags = 0; + break; + } + nq = q->m_nextpkt; + m->m_nextpkt = nq; + IPSTAT_INC(ips_fragdropped); + fp->ipq_nfrags--; + m_freem(q); + } + + /* + * Check for complete reassembly and perform frag per packet + * limiting. + * + * Frag limiting is performed here so that the nth frag has + * a chance to complete the packet before we drop the packet. + * As a result, n+1 frags are actually allowed per packet, but + * only n will ever be stored. (n = maxfragsperpacket.) + * + */ + next = 0; + for (p = NULL, q = fp->ipq_frags; q; p = q, q = q->m_nextpkt) { + if (ntohs(GETIP(q)->ip_off) != next) { + if (fp->ipq_nfrags > V_maxfragsperpacket) + ipq_drop(head, fp); + goto done; + } + next += ntohs(GETIP(q)->ip_len); + } + /* Make sure the last packet didn't have the IP_MF flag */ + if (p->m_flags & M_IP_FRAG) { + if (fp->ipq_nfrags > V_maxfragsperpacket) + ipq_drop(head, fp); + goto done; + } + + /* + * Reassembly is complete. Make sure the packet is a sane size. + */ + q = fp->ipq_frags; + ip = GETIP(q); + if (next + (ip->ip_hl << 2) > IP_MAXPACKET) { + IPSTAT_INC(ips_toolong); + ipq_drop(head, fp); + goto done; + } + + /* + * Concatenate fragments. + */ + m = q; + t = m->m_next; + m->m_next = NULL; + m_cat(m, t); + nq = q->m_nextpkt; + q->m_nextpkt = NULL; + for (q = nq; q != NULL; q = nq) { + nq = q->m_nextpkt; + q->m_nextpkt = NULL; + m->m_pkthdr.csum_flags &= q->m_pkthdr.csum_flags; + m->m_pkthdr.csum_data += q->m_pkthdr.csum_data; + m_cat(m, q); + } + /* + * In order to do checksumming faster we do 'end-around carry' here + * (and not in for{} loop), though it implies we are not going to + * reassemble more than 64k fragments. + */ + while (m->m_pkthdr.csum_data & 0xffff0000) + m->m_pkthdr.csum_data = (m->m_pkthdr.csum_data & 0xffff) + + (m->m_pkthdr.csum_data >> 16); +#ifdef MAC + mac_ipq_reassemble(fp, m); + mac_ipq_destroy(fp); +#endif + + /* + * Create header for new ip packet by modifying header of first + * packet; dequeue and discard fragment reassembly header. + * Make header visible. + */ + ip->ip_len = htons((ip->ip_hl << 2) + next); + ip->ip_src = fp->ipq_src; + ip->ip_dst = fp->ipq_dst; + TAILQ_REMOVE(head, fp, ipq_list); + uma_zfree(V_ipq_zone, fp); + m->m_len += (ip->ip_hl << 2); + m->m_data -= (ip->ip_hl << 2); + /* some debugging cruft by sklower, below, will go away soon */ + if (m->m_flags & M_PKTHDR) /* XXX this should be done elsewhere */ + m_fixhdr(m); + IPSTAT_INC(ips_reassembled); + IPQ_UNLOCK(hash); + +#ifdef RSS + /* + * Query the RSS layer for the flowid / flowtype for the + * mbuf payload. + * + * For now, just assume we have to calculate a new one. + * Later on we should check to see if the assigned flowid matches + * what RSS wants for the given IP protocol and if so, just keep it. + * + * We then queue into the relevant netisr so it can be dispatched + * to the correct CPU. + * + * Note - this may return 1, which means the flowid in the mbuf + * is correct for the configured RSS hash types and can be used. + */ + if (rss_mbuf_software_hash_v4(m, 0, &rss_hash, &rss_type) == 0) { + m->m_pkthdr.flowid = rss_hash; + M_HASHTYPE_SET(m, rss_type); + } + + /* + * Queue/dispatch for reprocessing. + * + * Note: this is much slower than just handling the frame in the + * current receive context. It's likely worth investigating + * why this is. + */ + netisr_dispatch(NETISR_IP_DIRECT, m); + return (NULL); +#endif + + /* Handle in-line */ + return (m); + +dropfrag: + IPSTAT_INC(ips_fragdropped); + if (fp != NULL) + fp->ipq_nfrags--; + m_freem(m); +done: + IPQ_UNLOCK(hash); + return (NULL); + +#undef GETIP +} + +/* + * Initialize IP reassembly structures. + */ +void +ipreass_init(void) +{ + + for (int i = 0; i < IPREASS_NHASH; i++) { + TAILQ_INIT(&V_ipq[i].head); + mtx_init(&V_ipq[i].lock, "IP reassembly", NULL, + MTX_DEF | MTX_DUPOK); + } + V_maxfragsperpacket = 16; + V_ipq_zone = uma_zcreate("ipq", sizeof(struct ipq), NULL, NULL, NULL, + NULL, UMA_ALIGN_PTR, 0); + uma_zone_set_max(V_ipq_zone, nmbclusters / 32); + + if (IS_DEFAULT_VNET(curvnet)) + EVENTHANDLER_REGISTER(nmbclusters_change, ipreass_zone_change, + NULL, EVENTHANDLER_PRI_ANY); +} + +/* + * If a timer expires on a reassembly queue, discard it. + */ +void +ipreass_slowtimo(void) +{ + struct ipq *fp, *tmp; + + for (int i = 0; i < IPREASS_NHASH; i++) { + IPQ_LOCK(i); + TAILQ_FOREACH_SAFE(fp, &V_ipq[i].head, ipq_list, tmp) + if (--fp->ipq_ttl == 0) + ipq_timeout(&V_ipq[i].head, fp); + IPQ_UNLOCK(i); + } +} + +/* + * Drain off all datagram fragments. + */ +void +ipreass_drain(void) +{ + + for (int i = 0; i < IPREASS_NHASH; i++) { + IPQ_LOCK(i); + while(!TAILQ_EMPTY(&V_ipq[i].head)) + ipq_drop(&V_ipq[i].head, TAILQ_FIRST(&V_ipq[i].head)); + IPQ_UNLOCK(i); + } +} + +#ifdef VIMAGE +/* + * Destroy IP reassembly structures. + */ +void +ipreass_destroy(void) +{ + + ipreass_drain(); + uma_zdestroy(V_ipq_zone); + for (int i = 0; i < IPREASS_NHASH; i++) + mtx_destroy(&V_ipq[i].lock); +} +#endif + +/* + * After maxnipq has been updated, propagate the change to UMA. The UMA zone + * max has slightly different semantics than the sysctl, for historical + * reasons. + */ +static void +ipreass_drain_tomax(void) +{ + int target; + + /* + * If we are over the maximum number of fragments, + * drain off enough to get down to the new limit, + * stripping off last elements on queues. Every + * run we strip the oldest element from each bucket. + */ + target = uma_zone_get_max(V_ipq_zone); + while (uma_zone_get_cur(V_ipq_zone) > target) { + struct ipq *fp; + + for (int i = 0; i < IPREASS_NHASH; i++) { + IPQ_LOCK(i); + fp = TAILQ_LAST(&V_ipq[i].head, ipqhead); + if (fp != NULL) + ipq_timeout(&V_ipq[i].head, fp); + IPQ_UNLOCK(i); + } + } +} + +static void +ipreass_zone_change(void *tag) +{ + + uma_zone_set_max(V_ipq_zone, nmbclusters / 32); + ipreass_drain_tomax(); +} + +/* + * Change the limit on the UMA zone, or disable the fragment allocation + * at all. Since 0 and -1 is a special values here, we need our own handler, + * instead of sysctl_handle_uma_zone_max(). + */ +static int +sysctl_maxfragpackets(SYSCTL_HANDLER_ARGS) +{ + int error, max; + + if (V_noreass == 0) { + max = uma_zone_get_max(V_ipq_zone); + if (max == 0) + max = -1; + } else + max = 0; + error = sysctl_handle_int(oidp, &max, 0, req); + if (error || !req->newptr) + return (error); + if (max > 0) { + /* + * XXXRW: Might be a good idea to sanity check the argument + * and place an extreme upper bound. + */ + max = uma_zone_set_max(V_ipq_zone, max); + ipreass_drain_tomax(); + V_noreass = 0; + } else if (max == 0) { + V_noreass = 1; + ipreass_drain(); + } else if (max == -1) { + V_noreass = 0; + uma_zone_set_max(V_ipq_zone, 0); + } else + return (EINVAL); + return (0); +} + +/* + * Seek for old fragment queue header that can be reused. Try to + * reuse a header from currently locked hash bucket. + */ +static struct ipq * +ipq_reuse(int start) +{ + struct ipq *fp; + int i; + + IPQ_LOCK_ASSERT(start); + + for (i = start;; i++) { + if (i == IPREASS_NHASH) + i = 0; + if (i != start && IPQ_TRYLOCK(i) == 0) + continue; + fp = TAILQ_LAST(&V_ipq[i].head, ipqhead); + if (fp) { + struct mbuf *m; + + IPSTAT_ADD(ips_fragtimeout, fp->ipq_nfrags); + while (fp->ipq_frags) { + m = fp->ipq_frags; + fp->ipq_frags = m->m_nextpkt; + m_freem(m); + } + TAILQ_REMOVE(&V_ipq[i].head, fp, ipq_list); + if (i != start) + IPQ_UNLOCK(i); + IPQ_LOCK_ASSERT(start); + return (fp); + } + if (i != start) + IPQ_UNLOCK(i); + } +} + +/* + * Free a fragment reassembly header and all associated datagrams. + */ +static void +ipq_free(struct ipqhead *fhp, struct ipq *fp) +{ + struct mbuf *q; + + while (fp->ipq_frags) { + q = fp->ipq_frags; + fp->ipq_frags = q->m_nextpkt; + m_freem(q); + } + TAILQ_REMOVE(fhp, fp, ipq_list); + uma_zfree(V_ipq_zone, fp); +}