myri10ge/drv/myri10ge_lro.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007-2009 Myricom, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef lint
static const char __idstring[] =
    "@(#)$Id: myri10ge_lro.c,v 1.7 2009-06-29 13:47:22 gallatin Exp $";
#endif

#include "myri10ge_var.h"

#define IP_OFFMASK 0x1fff
#define TCPOPT_TIMESTAMP 8
#define TCPOLEN_TIMESTAMP 10
#define TCPOLEN_TSTAMP_APPA 12


/*
 * Assume len is a multiple of 4. Note that "raw" must be
 * suitably aligned. In practice, it will always enter algned on
 * at least a 4 bytes bounday, due to the alignment of our rx buffers.
 */
uint16_t
myri10ge_csum_generic(uint16_t *raw, int len)
{
    uint32_t csum;
    csum = 0;
    while (len > 0) {
        csum += *raw;
        raw++;
        csum += *raw;
        raw++;
        len -= 4;
    }
    csum = (csum >> 16) + (csum & 0xffff);
    csum = (csum >> 16) + (csum & 0xffff);
    return ((uint16_t)csum);
}

static uint16_t
myri10ge_in_pseudo(unsigned int a, unsigned int b,
    unsigned int c)
{
    uint64_t csum;

    csum = (uint64_t)a + b + c;
    csum = (csum >> 16) + (csum & 0xffff);
    csum = (csum >> 16) + (csum & 0xffff);
    return ((uint16_t)csum);
}

void
myri10ge_lro_flush(struct myri10ge_slice_state *ss, struct lro_entry *lro,
    struct myri10ge_mblk_list *mbl)
{
    struct ip *ip;
    struct tcphdr *tcp;
    uint32_t *ts_ptr;
    uint32_t tcplen, tcp_csum;

    if (lro->append_cnt) {
        /*
         * incorporate the new len into the ip header and
         * re-calculate the checksum
         */
        ip = lro->ip;
        ip->ip_len = htons(lro->len - ETHERNET_HEADER_SIZE);
        ip->ip_sum = 0;
        ip->ip_sum = 0xffff ^
            myri10ge_csum_generic((uint16_t *)ip, sizeof (*ip));
        /* incorporate the latest ack into the tcp header */
        tcp = (struct tcphdr *)(ip + 1);
        tcp->th_ack = lro->ack_seq;
        tcp->th_win = lro->window;
        tcp->th_flags = lro->flags;
        /* incorporate latest timestamp into the tcp header */
        if (lro->timestamp) {
            ts_ptr = (uint32_t *)(tcp + 1);
            ts_ptr[1] = htonl(lro->tsval);
            ts_ptr[2] = lro->tsecr;
        }
        /*
         * update checksum in tcp header by re-calculating the
         * tcp pseudoheader checksum, and adding it to the checksum
         * of the tcp payload data
         */
        tcp->th_sum = 0;
        tcplen = lro->len - sizeof (*ip) - ETHERNET_HEADER_SIZE;
        tcp_csum = lro->data_csum;
        tcp_csum += myri10ge_in_pseudo(ip->ip_src.s_addr,
            ip->ip_dst.s_addr, htons(tcplen + IPPROTO_TCP));
        tcp_csum += myri10ge_csum_generic((uint16_t *)tcp,
            tcp->th_off << 2);
        tcp_csum = (tcp_csum & 0xffff) + (tcp_csum >> 16);
        tcp_csum = (tcp_csum & 0xffff) + (tcp_csum >> 16);
        tcp->th_sum = 0xffff ^ tcp_csum;
    }

    mac_hcksum_set(lro->m_head, 0, 0, 0,
        0, HCK_IPV4_HDRCKSUM_OK | HCK_FULLCKSUM_OK);

    mbl->cnt += lro->append_cnt;
    myri10ge_mbl_append(ss, mbl, lro->m_head);
    MYRI10GE_SLICE_STAT_INC(lro_flushed);
    MYRI10GE_SLICE_STAT_ADD(lro_queued, lro->append_cnt + 1);
    lro->m_head = NULL;
    lro->timestamp = 0;
    lro->append_cnt = 0;
    lro->next = ss->lro_free;
    ss->lro_free = lro;
}

int
myri10ge_lro_rx(struct myri10ge_slice_state *ss, mblk_t *m_head,
        uint32_t csum, struct myri10ge_mblk_list *mbl)
{
    struct ether_header *eh;
    struct ip *ip;
    struct tcphdr *tcp;
    uint32_t *ts_ptr;
    struct lro_entry *lro, *curr;
    int hlen, ip_len, tcp_hdr_len, tcp_data_len;
    int opt_bytes, trim;
    int tot_len = MBLKL(m_head);
    uint32_t seq, tmp_csum;

    eh = (struct ether_header *)(void *)m_head->b_rptr;
    if (eh->ether_type != htons(ETHERTYPE_IP))
        return (EINVAL);
    ip = (struct ip *)(void *)(eh + 1);
    if (ip->ip_p != IPPROTO_TCP)
        return (EINVAL);

    /* ensure there are no options */
    if ((ip->ip_hl << 2) != sizeof (*ip))
        return (EINVAL);

    /* .. and the packet is not fragmented */
    if (ip->ip_off & htons(IP_MF|IP_OFFMASK))
        return (EINVAL);

    /* verify that the IP header checksum is correct */
    tmp_csum = myri10ge_csum_generic((uint16_t *)ip, sizeof (*ip));
    if (unlikely((tmp_csum ^ 0xffff) != 0)) {
        MYRI10GE_SLICE_STAT_INC(lro_bad_csum);
        return (EINVAL);
    }

    /* find the TCP header */
    tcp = (struct tcphdr *)(ip + 1);

    /* ensure no bits set besides ack or psh */
    if ((tcp->th_flags & ~(TH_ACK | TH_PUSH)) != 0)
        return (EINVAL);

    /*
     * check for timestamps. Since the only option we handle are
     * timestamps, we only have to handle the simple case of
     * aligned timestamps
     */

    opt_bytes = (tcp->th_off << 2) - sizeof (*tcp);
    tcp_hdr_len =  sizeof (*tcp) + opt_bytes;
    ts_ptr = (uint32_t *)(tcp + 1);
    if (opt_bytes != 0) {
        if (unlikely(opt_bytes != TCPOLEN_TSTAMP_APPA) ||
            (*ts_ptr !=  ntohl(TCPOPT_NOP<<24|TCPOPT_NOP<<16|
            TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)))
            return (EINVAL);
    }

    ip_len = ntohs(ip->ip_len);
    tcp_data_len = ip_len - (tcp->th_off << 2) - sizeof (*ip);

    /*
     * If frame is padded beyond the end of the IP packet,
     * then we must trim the extra bytes off the end.
     */
    trim = tot_len - (ip_len + ETHERNET_HEADER_SIZE);
    if (trim != 0) {
        if (trim < 0) {
            /* truncated packet */
            return (EINVAL);
        }
        m_head->b_wptr -= trim;
        tot_len -= trim;
    }

    /* Verify TCP checksum */
    csum = ntohs((uint16_t)csum);
    tmp_csum = csum + myri10ge_in_pseudo(ip->ip_src.s_addr,
        ip->ip_dst.s_addr, htons(tcp_hdr_len + tcp_data_len + IPPROTO_TCP));
    tmp_csum = (tmp_csum & 0xffff) + (tmp_csum >> 16);
    tmp_csum = (tmp_csum & 0xffff) + (tmp_csum >> 16);
    if (tmp_csum != 0xffff) {
        MYRI10GE_SLICE_STAT_INC(lro_bad_csum);
        return (EINVAL);
    }

    hlen = ip_len + ETHERNET_HEADER_SIZE - tcp_data_len;
    seq = ntohl(tcp->th_seq);

    for (lro = ss->lro_active; lro != NULL; lro = lro->next) {
        if (lro->source_port == tcp->th_sport &&
            lro->dest_port == tcp->th_dport &&
            lro->source_ip == ip->ip_src.s_addr &&
            lro->dest_ip == ip->ip_dst.s_addr) {
            /* Try to append it */

            if (unlikely(seq != lro->next_seq)) {
                /* out of order packet */
                if (ss->lro_active == lro) {
                    ss->lro_active = lro->next;
                } else {
                    curr = ss->lro_active;
                    while (curr->next != lro)
                        curr = curr->next;
                    curr->next = lro->next;
                }
                myri10ge_lro_flush(ss, lro, mbl);
                return (EINVAL);
            }

            if (opt_bytes) {
                uint32_t tsval = ntohl(*(ts_ptr + 1));
                /* make sure timestamp values are increasing */
                if (unlikely(lro->tsval > tsval ||
                    *(ts_ptr + 2) == 0)) {
                    return (-8);
                }
                lro->tsval = tsval;
                lro->tsecr = *(ts_ptr + 2);
            }

            lro->next_seq += tcp_data_len;
            lro->ack_seq = tcp->th_ack;
            lro->window = tcp->th_win;
            lro->flags |= tcp->th_flags;
            lro->append_cnt++;
            if (tcp_data_len == 0) {
                freeb(m_head);
                return (0);
            }
            /*
             * subtract off the checksum of the tcp header
             * from the hardware checksum, and add it to
             * the stored tcp data checksum.  Byteswap
             * the checksum if the total length so far is
             * odd
             */
            tmp_csum = myri10ge_csum_generic((uint16_t *)tcp,
                tcp_hdr_len);
            csum = csum + (tmp_csum ^ 0xffff);
            csum = (csum & 0xffff) + (csum >> 16);
            csum = (csum & 0xffff) + (csum >> 16);
            if (lro->len & 0x1) {
                /* Odd number of bytes so far, flip bytes */
                csum = ((csum << 8) | (csum >> 8)) & 0xffff;
            }
            csum = csum + lro->data_csum;
            csum = (csum & 0xffff) + (csum >> 16);
            csum = (csum & 0xffff) + (csum >> 16);
            lro->data_csum = csum;

            lro->len += tcp_data_len;

            /*
             * adjust mblk so that rptr points to
             * the first byte of the payload
             */
            m_head->b_rptr += hlen;
            /* append mbuf chain */
            lro->m_tail->b_cont = m_head;
            /* advance the last pointer */
            lro->m_tail = m_head;
            /* flush packet if required */
            if (lro->len > (65535 - myri10ge_mtu) ||
                (lro->append_cnt + 1) == myri10ge_lro_max_aggr) {
                if (ss->lro_active == lro) {
                    ss->lro_active = lro->next;
                } else {
                    curr = ss->lro_active;
                    while (curr->next != lro)
                        curr = curr->next;
                    curr->next = lro->next;
                }
                myri10ge_lro_flush(ss, lro, mbl);
            }
            return (0);
        }
    }

    if (ss->lro_free == NULL)
        return (ENOMEM);

    /* start a new chain */
    lro = ss->lro_free;
    ss->lro_free = lro->next;
    lro->next = ss->lro_active;
    ss->lro_active = lro;
    lro->source_port = tcp->th_sport;
    lro->dest_port = tcp->th_dport;
    lro->source_ip = ip->ip_src.s_addr;
    lro->dest_ip = ip->ip_dst.s_addr;
    lro->next_seq = seq + tcp_data_len;
    lro->mss = (uint16_t)tcp_data_len;
    lro->ack_seq = tcp->th_ack;
    lro->window = tcp->th_win;
    lro->flags = tcp->th_flags;

    /*
     * save the checksum of just the TCP payload by
     * subtracting off the checksum of the TCP header from
     * the entire hardware checksum
     * Since IP header checksum is correct, checksum over
     * the IP header is -0.  Substracting -0 is unnecessary.
     */
    tmp_csum = myri10ge_csum_generic((uint16_t *)tcp, tcp_hdr_len);
    csum = csum + (tmp_csum ^ 0xffff);
    csum = (csum & 0xffff) + (csum >> 16);
    csum = (csum & 0xffff) + (csum >> 16);
    lro->data_csum = csum;
    lro->ip = ip;

    /* record timestamp if it is present */
    if (opt_bytes) {
        lro->timestamp = 1;
        lro->tsval = ntohl(*(ts_ptr + 1));
        lro->tsecr = *(ts_ptr + 2);
    }
    lro->len = tot_len;
    lro->m_head = m_head;
    lro->m_tail = m_head;
    return (0);
}

/*
 *  This file uses MyriGE driver indentation.
 *
 * Local Variables:
 * c-file-style:"sun"
 * tab-width:8
 * End:
 */