/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2007, Myricom Inc. * Copyright (c) 2008, Intel Corporation. * Copyright (c) 2012 The FreeBSD Foundation * Copyright (c) 2016-2021 Mellanox Technologies. * All rights reserved. * * Portions of this software were developed by Bjoern Zeeb * under sponsorship from the FreeBSD Foundation. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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. */ #include #include "opt_inet.h" #include "opt_inet6.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static MALLOC_DEFINE(M_LRO, "LRO", "LRO control structures"); static void tcp_lro_rx_done(struct lro_ctrl *lc); static int tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, bool use_hash); SYSCTL_NODE(_net_inet_tcp, OID_AUTO, lro, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, "TCP LRO"); long tcplro_stacks_wanting_mbufq; int (*tcp_lro_flush_tcphpts)(struct lro_ctrl *lc, struct lro_entry *le); counter_u64_t tcp_inp_lro_direct_queue; counter_u64_t tcp_inp_lro_wokeup_queue; counter_u64_t tcp_inp_lro_compressed; counter_u64_t tcp_inp_lro_locks_taken; counter_u64_t tcp_extra_mbuf; counter_u64_t tcp_would_have_but; counter_u64_t tcp_comp_total; counter_u64_t tcp_uncomp_total; counter_u64_t tcp_bad_csums; static unsigned tcp_lro_entries = TCP_LRO_ENTRIES; SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, entries, CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_entries, 0, "default number of LRO entries"); static uint32_t tcp_lro_cpu_set_thresh = TCP_LRO_CPU_DECLARATION_THRESH; SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, lro_cpu_threshold, CTLFLAG_RDTUN | CTLFLAG_MPSAFE, &tcp_lro_cpu_set_thresh, 0, "Number of interrupts in a row on the same CPU that will make us declare an 'affinity' cpu?"); static uint32_t tcp_less_accurate_lro_ts = 0; SYSCTL_UINT(_net_inet_tcp_lro, OID_AUTO, lro_less_accurate, CTLFLAG_MPSAFE, &tcp_less_accurate_lro_ts, 0, "Do we trade off efficency by doing less timestamp operations for time accuracy?"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, fullqueue, CTLFLAG_RD, &tcp_inp_lro_direct_queue, "Number of lro's fully queued to transport"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, wokeup, CTLFLAG_RD, &tcp_inp_lro_wokeup_queue, "Number of lro's where we woke up transport via hpts"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, compressed, CTLFLAG_RD, &tcp_inp_lro_compressed, "Number of lro's compressed and sent to transport"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, lockcnt, CTLFLAG_RD, &tcp_inp_lro_locks_taken, "Number of lro's inp_wlocks taken"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, extra_mbuf, CTLFLAG_RD, &tcp_extra_mbuf, "Number of times we had an extra compressed ack dropped into the tp"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, would_have_but, CTLFLAG_RD, &tcp_would_have_but, "Number of times we would have had an extra compressed, but mget failed"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, with_m_ackcmp, CTLFLAG_RD, &tcp_comp_total, "Number of mbufs queued with M_ACKCMP flags set"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, without_m_ackcmp, CTLFLAG_RD, &tcp_uncomp_total, "Number of mbufs queued without M_ACKCMP"); SYSCTL_COUNTER_U64(_net_inet_tcp_lro, OID_AUTO, lro_badcsum, CTLFLAG_RD, &tcp_bad_csums, "Number of packets that the common code saw with bad csums"); void tcp_lro_reg_mbufq(void) { atomic_fetchadd_long(&tcplro_stacks_wanting_mbufq, 1); } void tcp_lro_dereg_mbufq(void) { atomic_fetchadd_long(&tcplro_stacks_wanting_mbufq, -1); } static __inline void tcp_lro_active_insert(struct lro_ctrl *lc, struct lro_head *bucket, struct lro_entry *le) { LIST_INSERT_HEAD(&lc->lro_active, le, next); LIST_INSERT_HEAD(bucket, le, hash_next); } static __inline void tcp_lro_active_remove(struct lro_entry *le) { LIST_REMOVE(le, next); /* active list */ LIST_REMOVE(le, hash_next); /* hash bucket */ } int tcp_lro_init(struct lro_ctrl *lc) { return (tcp_lro_init_args(lc, NULL, tcp_lro_entries, 0)); } int tcp_lro_init_args(struct lro_ctrl *lc, struct ifnet *ifp, unsigned lro_entries, unsigned lro_mbufs) { struct lro_entry *le; size_t size; unsigned i, elements; lc->lro_bad_csum = 0; lc->lro_queued = 0; lc->lro_flushed = 0; lc->lro_mbuf_count = 0; lc->lro_mbuf_max = lro_mbufs; lc->lro_cnt = lro_entries; lc->lro_ackcnt_lim = TCP_LRO_ACKCNT_MAX; lc->lro_length_lim = TCP_LRO_LENGTH_MAX; lc->ifp = ifp; LIST_INIT(&lc->lro_free); LIST_INIT(&lc->lro_active); /* create hash table to accelerate entry lookup */ if (lro_entries > lro_mbufs) elements = lro_entries; else elements = lro_mbufs; lc->lro_hash = phashinit_flags(elements, M_LRO, &lc->lro_hashsz, HASH_NOWAIT); if (lc->lro_hash == NULL) { memset(lc, 0, sizeof(*lc)); return (ENOMEM); } /* compute size to allocate */ size = (lro_mbufs * sizeof(struct lro_mbuf_sort)) + (lro_entries * sizeof(*le)); lc->lro_mbuf_data = (struct lro_mbuf_sort *) malloc(size, M_LRO, M_NOWAIT | M_ZERO); /* check for out of memory */ if (lc->lro_mbuf_data == NULL) { free(lc->lro_hash, M_LRO); memset(lc, 0, sizeof(*lc)); return (ENOMEM); } /* compute offset for LRO entries */ le = (struct lro_entry *) (lc->lro_mbuf_data + lro_mbufs); /* setup linked list */ for (i = 0; i != lro_entries; i++) LIST_INSERT_HEAD(&lc->lro_free, le + i, next); return (0); } struct vxlan_header { uint32_t vxlh_flags; uint32_t vxlh_vni; }; static inline void * tcp_lro_low_level_parser(void *ptr, struct lro_parser *parser, bool update_data, bool is_vxlan, int mlen) { const struct ether_vlan_header *eh; void *old; uint16_t eth_type; if (update_data) memset(parser, 0, sizeof(*parser)); old = ptr; if (is_vxlan) { const struct vxlan_header *vxh; vxh = ptr; ptr = (uint8_t *)ptr + sizeof(*vxh); if (update_data) { parser->data.vxlan_vni = vxh->vxlh_vni & htonl(0xffffff00); } } eh = ptr; if (__predict_false(eh->evl_encap_proto == htons(ETHERTYPE_VLAN))) { eth_type = eh->evl_proto; if (update_data) { /* strip priority and keep VLAN ID only */ parser->data.vlan_id = eh->evl_tag & htons(EVL_VLID_MASK); } /* advance to next header */ ptr = (uint8_t *)ptr + ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN; mlen -= (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN); } else { eth_type = eh->evl_encap_proto; /* advance to next header */ mlen -= ETHER_HDR_LEN; ptr = (uint8_t *)ptr + ETHER_HDR_LEN; } if (__predict_false(mlen <= 0)) return (NULL); switch (eth_type) { #ifdef INET case htons(ETHERTYPE_IP): parser->ip4 = ptr; if (__predict_false(mlen < sizeof(struct ip))) return (NULL); /* Ensure there are no IPv4 options. */ if ((parser->ip4->ip_hl << 2) != sizeof (*parser->ip4)) break; /* .. and the packet is not fragmented. */ if (parser->ip4->ip_off & htons(IP_MF|IP_OFFMASK)) break; /* .. and the packet has valid src/dst addrs */ if (__predict_false(parser->ip4->ip_src.s_addr == INADDR_ANY || parser->ip4->ip_dst.s_addr == INADDR_ANY)) break; ptr = (uint8_t *)ptr + (parser->ip4->ip_hl << 2); mlen -= sizeof(struct ip); if (update_data) { parser->data.s_addr.v4 = parser->ip4->ip_src; parser->data.d_addr.v4 = parser->ip4->ip_dst; } switch (parser->ip4->ip_p) { case IPPROTO_UDP: if (__predict_false(mlen < sizeof(struct udphdr))) return (NULL); parser->udp = ptr; if (update_data) { parser->data.lro_type = LRO_TYPE_IPV4_UDP; parser->data.s_port = parser->udp->uh_sport; parser->data.d_port = parser->udp->uh_dport; } else { MPASS(parser->data.lro_type == LRO_TYPE_IPV4_UDP); } ptr = ((uint8_t *)ptr + sizeof(*parser->udp)); parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old; return (ptr); case IPPROTO_TCP: parser->tcp = ptr; if (__predict_false(mlen < sizeof(struct tcphdr))) return (NULL); if (update_data) { parser->data.lro_type = LRO_TYPE_IPV4_TCP; parser->data.s_port = parser->tcp->th_sport; parser->data.d_port = parser->tcp->th_dport; } else { MPASS(parser->data.lro_type == LRO_TYPE_IPV4_TCP); } if (__predict_false(mlen < (parser->tcp->th_off << 2))) return (NULL); ptr = (uint8_t *)ptr + (parser->tcp->th_off << 2); parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old; return (ptr); default: break; } break; #endif #ifdef INET6 case htons(ETHERTYPE_IPV6): parser->ip6 = ptr; if (__predict_false(mlen < sizeof(struct ip6_hdr))) return (NULL); /* Ensure the packet has valid src/dst addrs */ if (__predict_false(IN6_IS_ADDR_UNSPECIFIED(&parser->ip6->ip6_src) || IN6_IS_ADDR_UNSPECIFIED(&parser->ip6->ip6_dst))) return (NULL); ptr = (uint8_t *)ptr + sizeof(*parser->ip6); if (update_data) { parser->data.s_addr.v6 = parser->ip6->ip6_src; parser->data.d_addr.v6 = parser->ip6->ip6_dst; } mlen -= sizeof(struct ip6_hdr); switch (parser->ip6->ip6_nxt) { case IPPROTO_UDP: if (__predict_false(mlen < sizeof(struct udphdr))) return (NULL); parser->udp = ptr; if (update_data) { parser->data.lro_type = LRO_TYPE_IPV6_UDP; parser->data.s_port = parser->udp->uh_sport; parser->data.d_port = parser->udp->uh_dport; } else { MPASS(parser->data.lro_type == LRO_TYPE_IPV6_UDP); } ptr = (uint8_t *)ptr + sizeof(*parser->udp); parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old; return (ptr); case IPPROTO_TCP: if (__predict_false(mlen < sizeof(struct tcphdr))) return (NULL); parser->tcp = ptr; if (update_data) { parser->data.lro_type = LRO_TYPE_IPV6_TCP; parser->data.s_port = parser->tcp->th_sport; parser->data.d_port = parser->tcp->th_dport; } else { MPASS(parser->data.lro_type == LRO_TYPE_IPV6_TCP); } if (__predict_false(mlen < (parser->tcp->th_off << 2))) return (NULL); ptr = (uint8_t *)ptr + (parser->tcp->th_off << 2); parser->total_hdr_len = (uint8_t *)ptr - (uint8_t *)old; return (ptr); default: break; } break; #endif default: break; } /* Invalid packet - cannot parse */ return (NULL); } static const int vxlan_csum = CSUM_INNER_L3_CALC | CSUM_INNER_L3_VALID | CSUM_INNER_L4_CALC | CSUM_INNER_L4_VALID; static inline struct lro_parser * tcp_lro_parser(struct mbuf *m, struct lro_parser *po, struct lro_parser *pi, bool update_data) { void *data_ptr; /* Try to parse outer headers first. */ data_ptr = tcp_lro_low_level_parser(m->m_data, po, update_data, false, m->m_len); if (data_ptr == NULL || po->total_hdr_len > m->m_len) return (NULL); if (update_data) { /* Store VLAN ID, if any. */ if (__predict_false(m->m_flags & M_VLANTAG)) { po->data.vlan_id = htons(m->m_pkthdr.ether_vtag) & htons(EVL_VLID_MASK); } /* Store decrypted flag, if any. */ if (__predict_false((m->m_pkthdr.csum_flags & CSUM_TLS_MASK) == CSUM_TLS_DECRYPTED)) po->data.lro_flags |= LRO_FLAG_DECRYPTED; } switch (po->data.lro_type) { case LRO_TYPE_IPV4_UDP: case LRO_TYPE_IPV6_UDP: /* Check for VXLAN headers. */ if ((m->m_pkthdr.csum_flags & vxlan_csum) != vxlan_csum) break; /* Try to parse inner headers. */ data_ptr = tcp_lro_low_level_parser(data_ptr, pi, update_data, true, (m->m_len - ((caddr_t)data_ptr - m->m_data))); if (data_ptr == NULL || (pi->total_hdr_len + po->total_hdr_len) > m->m_len) break; /* Verify supported header types. */ switch (pi->data.lro_type) { case LRO_TYPE_IPV4_TCP: case LRO_TYPE_IPV6_TCP: return (pi); default: break; } break; case LRO_TYPE_IPV4_TCP: case LRO_TYPE_IPV6_TCP: if (update_data) memset(pi, 0, sizeof(*pi)); return (po); default: break; } return (NULL); } static inline int tcp_lro_trim_mbuf_chain(struct mbuf *m, const struct lro_parser *po) { int len; switch (po->data.lro_type) { #ifdef INET case LRO_TYPE_IPV4_TCP: len = ((uint8_t *)po->ip4 - (uint8_t *)m->m_data) + ntohs(po->ip4->ip_len); break; #endif #ifdef INET6 case LRO_TYPE_IPV6_TCP: len = ((uint8_t *)po->ip6 - (uint8_t *)m->m_data) + ntohs(po->ip6->ip6_plen) + sizeof(*po->ip6); break; #endif default: return (TCP_LRO_CANNOT); } /* * If the frame is padded beyond the end of the IP packet, * then trim the extra bytes off: */ if (__predict_true(m->m_pkthdr.len == len)) { return (0); } else if (m->m_pkthdr.len > len) { m_adj(m, len - m->m_pkthdr.len); return (0); } return (TCP_LRO_CANNOT); } static void lro_free_mbuf_chain(struct mbuf *m) { struct mbuf *save; while (m) { save = m->m_nextpkt; m->m_nextpkt = NULL; m_freem(m); m = save; } } void tcp_lro_free(struct lro_ctrl *lc) { struct lro_entry *le; unsigned x; /* reset LRO free list */ LIST_INIT(&lc->lro_free); /* free active mbufs, if any */ while ((le = LIST_FIRST(&lc->lro_active)) != NULL) { tcp_lro_active_remove(le); lro_free_mbuf_chain(le->m_head); } /* free hash table */ free(lc->lro_hash, M_LRO); lc->lro_hash = NULL; lc->lro_hashsz = 0; /* free mbuf array, if any */ for (x = 0; x != lc->lro_mbuf_count; x++) m_freem(lc->lro_mbuf_data[x].mb); lc->lro_mbuf_count = 0; /* free allocated memory, if any */ free(lc->lro_mbuf_data, M_LRO); lc->lro_mbuf_data = NULL; } static uint16_t tcp_lro_rx_csum_tcphdr(const struct tcphdr *th) { const uint16_t *ptr; uint32_t csum; uint16_t len; csum = -th->th_sum; /* exclude checksum field */ len = th->th_off; ptr = (const uint16_t *)th; while (len--) { csum += *ptr; ptr++; csum += *ptr; ptr++; } while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); return (csum); } static uint16_t tcp_lro_rx_csum_data(const struct lro_parser *pa, uint16_t tcp_csum) { uint32_t c; uint16_t cs; c = tcp_csum; switch (pa->data.lro_type) { #ifdef INET6 case LRO_TYPE_IPV6_TCP: /* Compute full pseudo IPv6 header checksum. */ cs = in6_cksum_pseudo(pa->ip6, ntohs(pa->ip6->ip6_plen), pa->ip6->ip6_nxt, 0); break; #endif #ifdef INET case LRO_TYPE_IPV4_TCP: /* Compute full pseudo IPv4 header checsum. */ cs = in_addword(ntohs(pa->ip4->ip_len) - sizeof(*pa->ip4), IPPROTO_TCP); cs = in_pseudo(pa->ip4->ip_src.s_addr, pa->ip4->ip_dst.s_addr, htons(cs)); break; #endif default: cs = 0; /* Keep compiler happy. */ break; } /* Complement checksum. */ cs = ~cs; c += cs; /* Remove TCP header checksum. */ cs = ~tcp_lro_rx_csum_tcphdr(pa->tcp); c += cs; /* Compute checksum remainder. */ while (c > 0xffff) c = (c >> 16) + (c & 0xffff); return (c); } static void tcp_lro_rx_done(struct lro_ctrl *lc) { struct lro_entry *le; while ((le = LIST_FIRST(&lc->lro_active)) != NULL) { tcp_lro_active_remove(le); tcp_lro_flush(lc, le); } } static void tcp_lro_flush_active(struct lro_ctrl *lc) { struct lro_entry *le; /* * Walk through the list of le entries, and * any one that does have packets flush. This * is called because we have an inbound packet * (e.g. SYN) that has to have all others flushed * in front of it. Note we have to do the remove * because tcp_lro_flush() assumes that the entry * is being freed. This is ok it will just get * reallocated again like it was new. */ LIST_FOREACH(le, &lc->lro_active, next) { if (le->m_head != NULL) { tcp_lro_active_remove(le); tcp_lro_flush(lc, le); } } } void tcp_lro_flush_inactive(struct lro_ctrl *lc, const struct timeval *timeout) { struct lro_entry *le, *le_tmp; uint64_t now, tov; struct bintime bt; NET_EPOCH_ASSERT(); if (LIST_EMPTY(&lc->lro_active)) return; /* get timeout time and current time in ns */ binuptime(&bt); now = bintime2ns(&bt); tov = ((timeout->tv_sec * 1000000000) + (timeout->tv_usec * 1000)); LIST_FOREACH_SAFE(le, &lc->lro_active, next, le_tmp) { if (now >= (bintime2ns(&le->alloc_time) + tov)) { tcp_lro_active_remove(le); tcp_lro_flush(lc, le); } } } #ifdef INET static int tcp_lro_rx_ipv4(struct lro_ctrl *lc, struct mbuf *m, struct ip *ip4) { uint16_t csum; /* Legacy IP has a header checksum that needs to be correct. */ if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) { if (__predict_false((m->m_pkthdr.csum_flags & CSUM_IP_VALID) == 0)) { lc->lro_bad_csum++; return (TCP_LRO_CANNOT); } } else { csum = in_cksum_hdr(ip4); if (__predict_false(csum != 0)) { lc->lro_bad_csum++; return (TCP_LRO_CANNOT); } } return (0); } #endif static inline void tcp_lro_assign_and_checksum_16(uint16_t *ptr, uint16_t value, uint16_t *psum) { uint32_t csum; csum = 0xffff - *ptr + value; while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); *ptr = value; *psum = csum; } static uint16_t tcp_lro_update_checksum(const struct lro_parser *pa, const struct lro_entry *le, uint16_t payload_len, uint16_t delta_sum) { uint32_t csum; uint16_t tlen; uint16_t temp[5] = {}; switch (pa->data.lro_type) { case LRO_TYPE_IPV4_TCP: /* Compute new IPv4 length. */ tlen = (pa->ip4->ip_hl << 2) + (pa->tcp->th_off << 2) + payload_len; tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]); /* Subtract delta from current IPv4 checksum. */ csum = pa->ip4->ip_sum + 0xffff - temp[0]; while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]); goto update_tcp_header; case LRO_TYPE_IPV6_TCP: /* Compute new IPv6 length. */ tlen = (pa->tcp->th_off << 2) + payload_len; tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]); goto update_tcp_header; case LRO_TYPE_IPV4_UDP: /* Compute new IPv4 length. */ tlen = (pa->ip4->ip_hl << 2) + sizeof(*pa->udp) + payload_len; tcp_lro_assign_and_checksum_16(&pa->ip4->ip_len, htons(tlen), &temp[0]); /* Subtract delta from current IPv4 checksum. */ csum = pa->ip4->ip_sum + 0xffff - temp[0]; while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); tcp_lro_assign_and_checksum_16(&pa->ip4->ip_sum, csum, &temp[1]); goto update_udp_header; case LRO_TYPE_IPV6_UDP: /* Compute new IPv6 length. */ tlen = sizeof(*pa->udp) + payload_len; tcp_lro_assign_and_checksum_16(&pa->ip6->ip6_plen, htons(tlen), &temp[0]); goto update_udp_header; default: return (0); } update_tcp_header: /* Compute current TCP header checksum. */ temp[2] = tcp_lro_rx_csum_tcphdr(pa->tcp); /* Incorporate the latest ACK into the TCP header. */ pa->tcp->th_ack = le->ack_seq; pa->tcp->th_win = le->window; /* Incorporate latest timestamp into the TCP header. */ if (le->timestamp != 0) { uint32_t *ts_ptr; ts_ptr = (uint32_t *)(pa->tcp + 1); ts_ptr[1] = htonl(le->tsval); ts_ptr[2] = le->tsecr; } /* Compute new TCP header checksum. */ temp[3] = tcp_lro_rx_csum_tcphdr(pa->tcp); /* Compute new TCP checksum. */ csum = pa->tcp->th_sum + 0xffff - delta_sum + 0xffff - temp[0] + 0xffff - temp[3] + temp[2]; while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); /* Assign new TCP checksum. */ tcp_lro_assign_and_checksum_16(&pa->tcp->th_sum, csum, &temp[4]); /* Compute all modififications affecting next checksum. */ csum = temp[0] + temp[1] + 0xffff - temp[2] + temp[3] + temp[4] + delta_sum; while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); /* Return delta checksum to next stage, if any. */ return (csum); update_udp_header: tlen = sizeof(*pa->udp) + payload_len; /* Assign new UDP length and compute checksum delta. */ tcp_lro_assign_and_checksum_16(&pa->udp->uh_ulen, htons(tlen), &temp[2]); /* Check if there is a UDP checksum. */ if (__predict_false(pa->udp->uh_sum != 0)) { /* Compute new UDP checksum. */ csum = pa->udp->uh_sum + 0xffff - delta_sum + 0xffff - temp[0] + 0xffff - temp[2]; while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); /* Assign new UDP checksum. */ tcp_lro_assign_and_checksum_16(&pa->udp->uh_sum, csum, &temp[3]); } /* Compute all modififications affecting next checksum. */ csum = temp[0] + temp[1] + temp[2] + temp[3] + delta_sum; while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); /* Return delta checksum to next stage, if any. */ return (csum); } static void tcp_flush_out_entry(struct lro_ctrl *lc, struct lro_entry *le) { /* Check if we need to recompute any checksums. */ if (le->needs_merge) { uint16_t csum; switch (le->inner.data.lro_type) { case LRO_TYPE_IPV4_TCP: csum = tcp_lro_update_checksum(&le->inner, le, le->m_head->m_pkthdr.lro_tcp_d_len, le->m_head->m_pkthdr.lro_tcp_d_csum); csum = tcp_lro_update_checksum(&le->outer, NULL, le->m_head->m_pkthdr.lro_tcp_d_len + le->inner.total_hdr_len, csum); le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID | CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID; le->m_head->m_pkthdr.csum_data = 0xffff; if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED)) le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED; break; case LRO_TYPE_IPV6_TCP: csum = tcp_lro_update_checksum(&le->inner, le, le->m_head->m_pkthdr.lro_tcp_d_len, le->m_head->m_pkthdr.lro_tcp_d_csum); csum = tcp_lro_update_checksum(&le->outer, NULL, le->m_head->m_pkthdr.lro_tcp_d_len + le->inner.total_hdr_len, csum); le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID | CSUM_PSEUDO_HDR; le->m_head->m_pkthdr.csum_data = 0xffff; if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED)) le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED; break; case LRO_TYPE_NONE: switch (le->outer.data.lro_type) { case LRO_TYPE_IPV4_TCP: csum = tcp_lro_update_checksum(&le->outer, le, le->m_head->m_pkthdr.lro_tcp_d_len, le->m_head->m_pkthdr.lro_tcp_d_csum); le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID | CSUM_PSEUDO_HDR | CSUM_IP_CHECKED | CSUM_IP_VALID; le->m_head->m_pkthdr.csum_data = 0xffff; if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED)) le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED; break; case LRO_TYPE_IPV6_TCP: csum = tcp_lro_update_checksum(&le->outer, le, le->m_head->m_pkthdr.lro_tcp_d_len, le->m_head->m_pkthdr.lro_tcp_d_csum); le->m_head->m_pkthdr.csum_flags = CSUM_DATA_VALID | CSUM_PSEUDO_HDR; le->m_head->m_pkthdr.csum_data = 0xffff; if (__predict_false(le->outer.data.lro_flags & LRO_FLAG_DECRYPTED)) le->m_head->m_pkthdr.csum_flags |= CSUM_TLS_DECRYPTED; break; default: break; } break; default: break; } } /* * Break any chain, this is not set to NULL on the singleton * case m_nextpkt points to m_head. Other case set them * m_nextpkt to NULL in push_and_replace. */ le->m_head->m_nextpkt = NULL; lc->lro_queued += le->m_head->m_pkthdr.lro_nsegs; (*lc->ifp->if_input)(lc->ifp, le->m_head); } static void tcp_set_entry_to_mbuf(struct lro_ctrl *lc, struct lro_entry *le, struct mbuf *m, struct tcphdr *th) { uint32_t *ts_ptr; uint16_t tcp_data_len; uint16_t tcp_opt_len; ts_ptr = (uint32_t *)(th + 1); tcp_opt_len = (th->th_off << 2); tcp_opt_len -= sizeof(*th); /* Check if there is a timestamp option. */ if (tcp_opt_len == 0 || __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA || *ts_ptr != TCP_LRO_TS_OPTION)) { /* We failed to find the timestamp option. */ le->timestamp = 0; } else { le->timestamp = 1; le->tsval = ntohl(*(ts_ptr + 1)); le->tsecr = *(ts_ptr + 2); } tcp_data_len = m->m_pkthdr.lro_tcp_d_len; /* Pull out TCP sequence numbers and window size. */ le->next_seq = ntohl(th->th_seq) + tcp_data_len; le->ack_seq = th->th_ack; le->window = th->th_win; le->flags = tcp_get_flags(th); le->needs_merge = 0; /* Setup new data pointers. */ le->m_head = m; le->m_tail = m_last(m); } static void tcp_push_and_replace(struct lro_ctrl *lc, struct lro_entry *le, struct mbuf *m) { struct lro_parser *pa; /* * Push up the stack of the current entry * and replace it with "m". */ struct mbuf *msave; /* Grab off the next and save it */ msave = le->m_head->m_nextpkt; le->m_head->m_nextpkt = NULL; /* Now push out the old entry */ tcp_flush_out_entry(lc, le); /* Re-parse new header, should not fail. */ pa = tcp_lro_parser(m, &le->outer, &le->inner, false); KASSERT(pa != NULL, ("tcp_push_and_replace: LRO parser failed on m=%p\n", m)); /* * Now to replace the data properly in the entry * we have to reset the TCP header and * other fields. */ tcp_set_entry_to_mbuf(lc, le, m, pa->tcp); /* Restore the next list */ m->m_nextpkt = msave; } static void tcp_lro_mbuf_append_pkthdr(struct lro_entry *le, const struct mbuf *p) { struct mbuf *m; uint32_t csum; m = le->m_head; if (m->m_pkthdr.lro_nsegs == 1) { /* Compute relative checksum. */ csum = p->m_pkthdr.lro_tcp_d_csum; } else { /* Merge TCP data checksums. */ csum = (uint32_t)m->m_pkthdr.lro_tcp_d_csum + (uint32_t)p->m_pkthdr.lro_tcp_d_csum; while (csum > 0xffff) csum = (csum >> 16) + (csum & 0xffff); } /* Update various counters. */ m->m_pkthdr.len += p->m_pkthdr.lro_tcp_d_len; m->m_pkthdr.lro_tcp_d_csum = csum; m->m_pkthdr.lro_tcp_d_len += p->m_pkthdr.lro_tcp_d_len; m->m_pkthdr.lro_nsegs += p->m_pkthdr.lro_nsegs; le->needs_merge = 1; } static void tcp_lro_condense(struct lro_ctrl *lc, struct lro_entry *le) { /* * Walk through the mbuf chain we * have on tap and compress/condense * as required. */ uint32_t *ts_ptr; struct mbuf *m; struct tcphdr *th; uint32_t tcp_data_len_total; uint32_t tcp_data_seg_total; uint16_t tcp_data_len; uint16_t tcp_opt_len; /* * First we must check the lead (m_head) * we must make sure that it is *not* * something that should be sent up * right away (sack etc). */ again: m = le->m_head->m_nextpkt; if (m == NULL) { /* Just one left. */ return; } th = tcp_lro_get_th(m); tcp_opt_len = (th->th_off << 2); tcp_opt_len -= sizeof(*th); ts_ptr = (uint32_t *)(th + 1); if (tcp_opt_len != 0 && __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA || *ts_ptr != TCP_LRO_TS_OPTION)) { /* * Its not the timestamp. We can't * use this guy as the head. */ le->m_head->m_nextpkt = m->m_nextpkt; tcp_push_and_replace(lc, le, m); goto again; } if ((tcp_get_flags(th) & ~(TH_ACK | TH_PUSH)) != 0) { /* * Make sure that previously seen segments/ACKs are delivered * before this segment, e.g. FIN. */ le->m_head->m_nextpkt = m->m_nextpkt; tcp_push_and_replace(lc, le, m); goto again; } while((m = le->m_head->m_nextpkt) != NULL) { /* * condense m into le, first * pull m out of the list. */ le->m_head->m_nextpkt = m->m_nextpkt; m->m_nextpkt = NULL; /* Setup my data */ tcp_data_len = m->m_pkthdr.lro_tcp_d_len; th = tcp_lro_get_th(m); ts_ptr = (uint32_t *)(th + 1); tcp_opt_len = (th->th_off << 2); tcp_opt_len -= sizeof(*th); tcp_data_len_total = le->m_head->m_pkthdr.lro_tcp_d_len + tcp_data_len; tcp_data_seg_total = le->m_head->m_pkthdr.lro_nsegs + m->m_pkthdr.lro_nsegs; if (tcp_data_seg_total >= lc->lro_ackcnt_lim || tcp_data_len_total >= lc->lro_length_lim) { /* Flush now if appending will result in overflow. */ tcp_push_and_replace(lc, le, m); goto again; } if (tcp_opt_len != 0 && __predict_false(tcp_opt_len != TCPOLEN_TSTAMP_APPA || *ts_ptr != TCP_LRO_TS_OPTION)) { /* * Maybe a sack in the new one? We need to * start all over after flushing the * current le. We will go up to the beginning * and flush it (calling the replace again possibly * or just returning). */ tcp_push_and_replace(lc, le, m); goto again; } if ((tcp_get_flags(th) & ~(TH_ACK | TH_PUSH)) != 0) { tcp_push_and_replace(lc, le, m); goto again; } if (tcp_opt_len != 0) { uint32_t tsval = ntohl(*(ts_ptr + 1)); /* Make sure timestamp values are increasing. */ if (TSTMP_GT(le->tsval, tsval)) { tcp_push_and_replace(lc, le, m); goto again; } le->tsval = tsval; le->tsecr = *(ts_ptr + 2); } /* Try to append the new segment. */ if (__predict_false(ntohl(th->th_seq) != le->next_seq || ((tcp_get_flags(th) & TH_ACK) != (le->flags & TH_ACK)) || (tcp_data_len == 0 && le->ack_seq == th->th_ack && le->window == th->th_win))) { /* Out of order packet, non-ACK + ACK or dup ACK. */ tcp_push_and_replace(lc, le, m); goto again; } if (tcp_data_len != 0 || SEQ_GT(ntohl(th->th_ack), ntohl(le->ack_seq))) { le->next_seq += tcp_data_len; le->ack_seq = th->th_ack; le->window = th->th_win; le->needs_merge = 1; } else if (th->th_ack == le->ack_seq) { if (WIN_GT(th->th_win, le->window)) { le->window = th->th_win; le->needs_merge = 1; } } if (tcp_data_len == 0) { m_freem(m); continue; } /* Merge TCP data checksum and length to head mbuf. */ tcp_lro_mbuf_append_pkthdr(le, m); /* * Adjust the mbuf so that m_data points to the first byte of * the ULP payload. Adjust the mbuf to avoid complications and * append new segment to existing mbuf chain. */ m_adj(m, m->m_pkthdr.len - tcp_data_len); m_demote_pkthdr(m); le->m_tail->m_next = m; le->m_tail = m_last(m); } } void tcp_lro_flush(struct lro_ctrl *lc, struct lro_entry *le) { /* Only optimise if there are multiple packets waiting. */ NET_EPOCH_ASSERT(); if (tcp_lro_flush_tcphpts == NULL || tcp_lro_flush_tcphpts(lc, le) != 0) { tcp_lro_condense(lc, le); tcp_flush_out_entry(lc, le); } lc->lro_flushed++; bzero(le, sizeof(*le)); LIST_INSERT_HEAD(&lc->lro_free, le, next); } #define tcp_lro_msb_64(x) (1ULL << (flsll(x) - 1)) /* * The tcp_lro_sort() routine is comparable to qsort(), except it has * a worst case complexity limit of O(MIN(N,64)*N), where N is the * number of elements to sort and 64 is the number of sequence bits * available. The algorithm is bit-slicing the 64-bit sequence number, * sorting one bit at a time from the most significant bit until the * least significant one, skipping the constant bits. This is * typically called a radix sort. */ static void tcp_lro_sort(struct lro_mbuf_sort *parray, uint32_t size) { struct lro_mbuf_sort temp; uint64_t ones; uint64_t zeros; uint32_t x; uint32_t y; repeat: /* for small arrays insertion sort is faster */ if (size <= 12) { for (x = 1; x < size; x++) { temp = parray[x]; for (y = x; y > 0 && temp.seq < parray[y - 1].seq; y--) parray[y] = parray[y - 1]; parray[y] = temp; } return; } /* compute sequence bits which are constant */ ones = 0; zeros = 0; for (x = 0; x != size; x++) { ones |= parray[x].seq; zeros |= ~parray[x].seq; } /* compute bits which are not constant into "ones" */ ones &= zeros; if (ones == 0) return; /* pick the most significant bit which is not constant */ ones = tcp_lro_msb_64(ones); /* * Move entries having cleared sequence bits to the beginning * of the array: */ for (x = y = 0; y != size; y++) { /* skip set bits */ if (parray[y].seq & ones) continue; /* swap entries */ temp = parray[x]; parray[x] = parray[y]; parray[y] = temp; x++; } KASSERT(x != 0 && x != size, ("Memory is corrupted\n")); /* sort zeros */ tcp_lro_sort(parray, x); /* sort ones */ parray += x; size -= x; goto repeat; } void tcp_lro_flush_all(struct lro_ctrl *lc) { uint64_t seq; uint64_t nseq; unsigned x; NET_EPOCH_ASSERT(); /* check if no mbufs to flush */ if (lc->lro_mbuf_count == 0) goto done; if (lc->lro_cpu_is_set == 0) { if (lc->lro_last_cpu == curcpu) { lc->lro_cnt_of_same_cpu++; /* Have we reached the threshold to declare a cpu? */ if (lc->lro_cnt_of_same_cpu > tcp_lro_cpu_set_thresh) lc->lro_cpu_is_set = 1; } else { lc->lro_last_cpu = curcpu; lc->lro_cnt_of_same_cpu = 0; } } CURVNET_SET(lc->ifp->if_vnet); /* get current time */ binuptime(&lc->lro_last_queue_time); /* sort all mbufs according to stream */ tcp_lro_sort(lc->lro_mbuf_data, lc->lro_mbuf_count); /* input data into LRO engine, stream by stream */ seq = 0; for (x = 0; x != lc->lro_mbuf_count; x++) { struct mbuf *mb; /* get mbuf */ mb = lc->lro_mbuf_data[x].mb; /* get sequence number, masking away the packet index */ nseq = lc->lro_mbuf_data[x].seq & (-1ULL << 24); /* check for new stream */ if (seq != nseq) { seq = nseq; /* flush active streams */ tcp_lro_rx_done(lc); } /* add packet to LRO engine */ if (tcp_lro_rx_common(lc, mb, 0, false) != 0) { /* Flush anything we have acummulated */ tcp_lro_flush_active(lc); /* input packet to network layer */ (*lc->ifp->if_input)(lc->ifp, mb); lc->lro_queued++; lc->lro_flushed++; } } CURVNET_RESTORE(); done: /* flush active streams */ tcp_lro_rx_done(lc); tcp_hpts_softclock(); lc->lro_mbuf_count = 0; } static struct lro_head * tcp_lro_rx_get_bucket(struct lro_ctrl *lc, struct mbuf *m, struct lro_parser *parser) { u_long hash; if (M_HASHTYPE_ISHASH(m)) { hash = m->m_pkthdr.flowid; } else { for (unsigned i = hash = 0; i != LRO_RAW_ADDRESS_MAX; i++) hash += parser->data.raw[i]; } return (&lc->lro_hash[hash % lc->lro_hashsz]); } static int tcp_lro_rx_common(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum, bool use_hash) { struct lro_parser pi; /* inner address data */ struct lro_parser po; /* outer address data */ struct lro_parser *pa; /* current parser for TCP stream */ struct lro_entry *le; struct lro_head *bucket; struct tcphdr *th; int tcp_data_len; int tcp_opt_len; int error; uint16_t tcp_data_sum; #ifdef INET /* Quickly decide if packet cannot be LRO'ed */ if (__predict_false(V_ipforwarding != 0)) return (TCP_LRO_CANNOT); #endif #ifdef INET6 /* Quickly decide if packet cannot be LRO'ed */ if (__predict_false(V_ip6_forwarding != 0)) return (TCP_LRO_CANNOT); #endif if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) != ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) || (m->m_pkthdr.csum_data != 0xffff)) { /* * The checksum either did not have hardware offload * or it was a bad checksum. We can't LRO such * a packet. */ counter_u64_add(tcp_bad_csums, 1); return (TCP_LRO_CANNOT); } /* We expect a contiguous header [eh, ip, tcp]. */ pa = tcp_lro_parser(m, &po, &pi, true); if (__predict_false(pa == NULL)) return (TCP_LRO_NOT_SUPPORTED); /* We don't expect any padding. */ error = tcp_lro_trim_mbuf_chain(m, pa); if (__predict_false(error != 0)) return (error); #ifdef INET switch (pa->data.lro_type) { case LRO_TYPE_IPV4_TCP: error = tcp_lro_rx_ipv4(lc, m, pa->ip4); if (__predict_false(error != 0)) return (error); break; default: break; } #endif /* If no hardware or arrival stamp on the packet add timestamp */ if ((m->m_flags & (M_TSTMP_LRO | M_TSTMP)) == 0) { m->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time); m->m_flags |= M_TSTMP_LRO; } /* Get pointer to TCP header. */ th = pa->tcp; /* Don't process SYN packets. */ if (__predict_false(tcp_get_flags(th) & TH_SYN)) return (TCP_LRO_CANNOT); /* Get total TCP header length and compute payload length. */ tcp_opt_len = (th->th_off << 2); tcp_data_len = m->m_pkthdr.len - ((uint8_t *)th - (uint8_t *)m->m_data) - tcp_opt_len; tcp_opt_len -= sizeof(*th); /* Don't process invalid TCP headers. */ if (__predict_false(tcp_opt_len < 0 || tcp_data_len < 0)) return (TCP_LRO_CANNOT); /* Compute TCP data only checksum. */ if (tcp_data_len == 0) tcp_data_sum = 0; /* no data, no checksum */ else if (__predict_false(csum != 0)) tcp_data_sum = tcp_lro_rx_csum_data(pa, ~csum); else tcp_data_sum = tcp_lro_rx_csum_data(pa, ~th->th_sum); /* Save TCP info in mbuf. */ m->m_nextpkt = NULL; m->m_pkthdr.rcvif = lc->ifp; m->m_pkthdr.lro_tcp_d_csum = tcp_data_sum; m->m_pkthdr.lro_tcp_d_len = tcp_data_len; m->m_pkthdr.lro_tcp_h_off = ((uint8_t *)th - (uint8_t *)m->m_data); m->m_pkthdr.lro_nsegs = 1; /* Get hash bucket. */ if (!use_hash) { bucket = &lc->lro_hash[0]; } else { bucket = tcp_lro_rx_get_bucket(lc, m, pa); } /* Try to find a matching previous segment. */ LIST_FOREACH(le, bucket, hash_next) { /* Compare addresses and ports. */ if (lro_address_compare(&po.data, &le->outer.data) == false || lro_address_compare(&pi.data, &le->inner.data) == false) continue; /* Check if no data and old ACK. */ if (tcp_data_len == 0 && SEQ_LT(ntohl(th->th_ack), ntohl(le->ack_seq))) { m_freem(m); return (0); } /* Mark "m" in the last spot. */ le->m_last_mbuf->m_nextpkt = m; /* Now set the tail to "m". */ le->m_last_mbuf = m; return (0); } /* Try to find an empty slot. */ if (LIST_EMPTY(&lc->lro_free)) return (TCP_LRO_NO_ENTRIES); /* Start a new segment chain. */ le = LIST_FIRST(&lc->lro_free); LIST_REMOVE(le, next); tcp_lro_active_insert(lc, bucket, le); /* Make sure the headers are set. */ le->inner = pi; le->outer = po; /* Store time this entry was allocated. */ le->alloc_time = lc->lro_last_queue_time; tcp_set_entry_to_mbuf(lc, le, m, th); /* Now set the tail to "m". */ le->m_last_mbuf = m; return (0); } int tcp_lro_rx(struct lro_ctrl *lc, struct mbuf *m, uint32_t csum) { int error; if (((m->m_pkthdr.csum_flags & (CSUM_DATA_VALID | CSUM_PSEUDO_HDR)) != ((CSUM_DATA_VALID | CSUM_PSEUDO_HDR))) || (m->m_pkthdr.csum_data != 0xffff)) { /* * The checksum either did not have hardware offload * or it was a bad checksum. We can't LRO such * a packet. */ counter_u64_add(tcp_bad_csums, 1); return (TCP_LRO_CANNOT); } /* get current time */ binuptime(&lc->lro_last_queue_time); CURVNET_SET(lc->ifp->if_vnet); error = tcp_lro_rx_common(lc, m, csum, true); if (__predict_false(error != 0)) { /* * Flush anything we have acummulated * ahead of this packet that can't * be LRO'd. This preserves order. */ tcp_lro_flush_active(lc); } CURVNET_RESTORE(); return (error); } void tcp_lro_queue_mbuf(struct lro_ctrl *lc, struct mbuf *mb) { NET_EPOCH_ASSERT(); /* sanity checks */ if (__predict_false(lc->ifp == NULL || lc->lro_mbuf_data == NULL || lc->lro_mbuf_max == 0)) { /* packet drop */ m_freem(mb); return; } /* check if packet is not LRO capable */ if (__predict_false((lc->ifp->if_capenable & IFCAP_LRO) == 0)) { /* input packet to network layer */ (*lc->ifp->if_input) (lc->ifp, mb); return; } /* If no hardware or arrival stamp on the packet add timestamp */ if ((tcplro_stacks_wanting_mbufq > 0) && (tcp_less_accurate_lro_ts == 0) && ((mb->m_flags & M_TSTMP) == 0)) { /* Add in an LRO time since no hardware */ binuptime(&lc->lro_last_queue_time); mb->m_pkthdr.rcv_tstmp = bintime2ns(&lc->lro_last_queue_time); mb->m_flags |= M_TSTMP_LRO; } /* create sequence number */ lc->lro_mbuf_data[lc->lro_mbuf_count].seq = (((uint64_t)M_HASHTYPE_GET(mb)) << 56) | (((uint64_t)mb->m_pkthdr.flowid) << 24) | ((uint64_t)lc->lro_mbuf_count); /* enter mbuf */ lc->lro_mbuf_data[lc->lro_mbuf_count].mb = mb; /* flush if array is full */ if (__predict_false(++lc->lro_mbuf_count == lc->lro_mbuf_max)) tcp_lro_flush_all(lc); } /* end */