net/smc/smc_clc.c

   1 /*
   2  *  Shared Memory Communications over RDMA (SMC-R) and RoCE
   3  *
   4  *  CLC (connection layer control) handshake over initial TCP socket to
   5  *  prepare for RDMA traffic
   6  *
   7  *  Copyright IBM Corp. 2016
   8  *
   9  *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
  10  */
  11
  12 #include <linux/in.h>
  13 #include <net/sock.h>
  14 #include <net/tcp.h>
  15
  16 #include "smc.h"
  17 #include "smc_clc.h"
  18 #include "smc_ib.h"
  19
  20 /* Wait for data on the tcp-socket, analyze received data
  21  * Returns:
  22  * 0 if success and it was not a decline that we received.
  23  * SMC_CLC_DECL_REPLY if decline received for fallback w/o another decl send.
  24  * clcsock error, -EINTR, -ECONNRESET, -EPROTO otherwise.
  25  */
  26 int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
  27                      u8 expected_type)
  28 {
  29         struct sock *clc_sk = smc->clcsock->sk;
  30         struct smc_clc_msg_hdr *clcm = buf;
  31         struct msghdr msg = {NULL, 0};
  32         int reason_code = 0;
  33         struct kvec vec;
  34         int len, datlen;
  35         int krflags;
  36
  37         /* peek the first few bytes to determine length of data to receive
  38          * so we don't consume any subsequent CLC message or payload data
  39          * in the TCP byte stream
  40          */
  41         vec.iov_base = buf;
  42         vec.iov_len = buflen;
  43         krflags = MSG_PEEK | MSG_WAITALL;
  44         smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
  45         len = kernel_recvmsg(smc->clcsock, &msg, &vec, 1,
  46                              sizeof(struct smc_clc_msg_hdr), krflags);
  47         if (signal_pending(current)) {
  48                 reason_code = -EINTR;
  49                 clc_sk->sk_err = EINTR;
  50                 smc->sk.sk_err = EINTR;
  51                 goto out;
  52         }
  53         if (clc_sk->sk_err) {
  54                 reason_code = -clc_sk->sk_err;
  55                 smc->sk.sk_err = clc_sk->sk_err;
  56                 goto out;
  57         }
  58         if (!len) { /* peer has performed orderly shutdown */
  59                 smc->sk.sk_err = ECONNRESET;
  60                 reason_code = -ECONNRESET;
  61                 goto out;
  62         }
  63         if (len < 0) {
  64                 smc->sk.sk_err = -len;
  65                 reason_code = len;
  66                 goto out;
  67         }
  68         datlen = ntohs(clcm->length);
  69         if ((len < sizeof(struct smc_clc_msg_hdr)) ||
  70             (datlen < sizeof(struct smc_clc_msg_decline)) ||
  71             (datlen > sizeof(struct smc_clc_msg_accept_confirm)) ||
  72             memcmp(clcm->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) ||
  73             ((clcm->type != SMC_CLC_DECLINE) &&
  74              (clcm->type != expected_type))) {
  75                 smc->sk.sk_err = EPROTO;
  76                 reason_code = -EPROTO;
  77                 goto out;
  78         }
  79
  80         /* receive the complete CLC message */
  81         vec.iov_base = buf;
  82         vec.iov_len = buflen;
  83         memset(&msg, 0, sizeof(struct msghdr));
  84         krflags = MSG_WAITALL;
  85         smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
  86         len = kernel_recvmsg(smc->clcsock, &msg, &vec, 1, datlen, krflags);
  87         if (len < datlen) {
  88                 smc->sk.sk_err = EPROTO;
  89                 reason_code = -EPROTO;
  90                 goto out;
  91         }
  92         if (clcm->type == SMC_CLC_DECLINE)
  93                 reason_code = SMC_CLC_DECL_REPLY;
  94 out:
  95         return reason_code;
  96 }
  97
  98 /* send CLC DECLINE message across internal TCP socket */
  99 int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info,
 100                          u8 out_of_sync)
 101 {
 102         struct smc_clc_msg_decline dclc;
 103         struct msghdr msg;
 104         struct kvec vec;
 105         int len;
 106
 107         memset(&dclc, 0, sizeof(dclc));
 108         memcpy(dclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 109         dclc.hdr.type = SMC_CLC_DECLINE;
 110         dclc.hdr.length = htons(sizeof(struct smc_clc_msg_decline));
 111         dclc.hdr.version = SMC_CLC_V1;
 112         dclc.hdr.flag = out_of_sync ? 1 : 0;
 113         memcpy(dclc.id_for_peer, local_systemid, sizeof(local_systemid));
 114         dclc.peer_diagnosis = htonl(peer_diag_info);
 115         memcpy(dclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 116
 117         memset(&msg, 0, sizeof(msg));
 118         vec.iov_base = &dclc;
 119         vec.iov_len = sizeof(struct smc_clc_msg_decline);
 120         len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
 121                              sizeof(struct smc_clc_msg_decline));
 122         if (len < sizeof(struct smc_clc_msg_decline))
 123                 smc->sk.sk_err = EPROTO;
 124         if (len < 0)
 125                 smc->sk.sk_err = -len;
 126         return len;
 127 }
 128
 129 /* send CLC PROPOSAL message across internal TCP socket */
 130 int smc_clc_send_proposal(struct smc_sock *smc,
 131                           struct smc_ib_device *smcibdev,
 132                           u8 ibport)
 133 {
 134         struct smc_clc_msg_proposal pclc;
 135         int reason_code = 0;
 136         struct msghdr msg;
 137         struct kvec vec;
 138         int len, rc;
 139
 140         /* send SMC Proposal CLC message */
 141         memset(&pclc, 0, sizeof(pclc));
 142         memcpy(pclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 143         pclc.hdr.type = SMC_CLC_PROPOSAL;
 144         pclc.hdr.length = htons(sizeof(pclc));
 145         pclc.hdr.version = SMC_CLC_V1;          /* SMC version */
 146         memcpy(pclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 147         memcpy(&pclc.lcl.gid, &smcibdev->gid[ibport - 1], SMC_GID_SIZE);
 148         memcpy(&pclc.lcl.mac, &smcibdev->mac[ibport - 1],
 149                sizeof(smcibdev->mac[ibport - 1]));
 150
 151         /* determine subnet and mask from internal TCP socket */
 152         rc = smc_netinfo_by_tcpsk(smc->clcsock, &pclc.outgoing_subnet,
 153                                   &pclc.prefix_len);
 154         if (rc)
 155                 return SMC_CLC_DECL_CNFERR; /* configuration error */
 156         memcpy(pclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 157         memset(&msg, 0, sizeof(msg));
 158         vec.iov_base = &pclc;
 159         vec.iov_len = sizeof(pclc);
 160         /* due to the few bytes needed for clc-handshake this cannot block */
 161         len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1, sizeof(pclc));
 162         if (len < sizeof(pclc)) {
 163                 if (len >= 0) {
 164                         reason_code = -ENETUNREACH;
 165                         smc->sk.sk_err = -reason_code;
 166                 } else {
 167                         smc->sk.sk_err = smc->clcsock->sk->sk_err;
 168                         reason_code = -smc->sk.sk_err;
 169                 }
 170         }
 171
 172         return reason_code;
 173 }
 174
 175 /* send CLC CONFIRM message across internal TCP socket */
 176 int smc_clc_send_confirm(struct smc_sock *smc)
 177 {
 178         struct smc_clc_msg_accept_confirm cclc;
 179         int reason_code = 0;
 180         struct msghdr msg;
 181         struct kvec vec;
 182         int len;
 183
 184         /* send SMC Confirm CLC msg */
 185         memset(&cclc, 0, sizeof(cclc));
 186         memcpy(cclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 187         cclc.hdr.type = SMC_CLC_CONFIRM;
 188         cclc.hdr.length = htons(sizeof(cclc));
 189         cclc.hdr.version = SMC_CLC_V1;          /* SMC version */
 190         memcpy(cclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 191
 192         /* tbd in follow-on patch: fill in link-related values */
 193
 194         /* tbd in follow-on patch: fill in rmb-related values */
 195
 196         cclc.conn_idx = 1; /* for now: 1 RMB = 1 RMBE */
 197
 198         memcpy(cclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 199
 200         memset(&msg, 0, sizeof(msg));
 201         vec.iov_base = &cclc;
 202         vec.iov_len = sizeof(cclc);
 203         len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1, sizeof(cclc));
 204         if (len < sizeof(cclc)) {
 205                 if (len >= 0) {
 206                         reason_code = -ENETUNREACH;
 207                         smc->sk.sk_err = -reason_code;
 208                 } else {
 209                         smc->sk.sk_err = smc->clcsock->sk->sk_err;
 210                         reason_code = -smc->sk.sk_err;
 211                 }
 212         }
 213         return reason_code;
 214 }
 215
 216 /* send CLC ACCEPT message across internal TCP socket */
 217 int smc_clc_send_accept(struct smc_sock *new_smc)
 218 {
 219         struct smc_clc_msg_accept_confirm aclc;
 220         struct msghdr msg;
 221         struct kvec vec;
 222         int rc = 0;
 223         int len;
 224
 225         memset(&aclc, 0, sizeof(aclc));
 226         memcpy(aclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 227         aclc.hdr.type = SMC_CLC_ACCEPT;
 228         aclc.hdr.length = htons(sizeof(aclc));
 229         aclc.hdr.version = SMC_CLC_V1;          /* SMC version */
 230         memcpy(aclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 231
 232         /* tbd in follow-on patch: fill in link-related values */
 233
 234         /* tbd in follow-on patch: fill in rmb-related values */
 235
 236         aclc.conn_idx = 1;                      /* as long as 1 RMB = 1 RMBE */
 237         memcpy(aclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 238
 239         memset(&msg, 0, sizeof(msg));
 240         vec.iov_base = &aclc;
 241         vec.iov_len = sizeof(aclc);
 242         len = kernel_sendmsg(new_smc->clcsock, &msg, &vec, 1, sizeof(aclc));
 243         if (len < sizeof(aclc)) {
 244                 if (len >= 0)
 245                         new_smc->sk.sk_err = EPROTO;
 246                 else
 247                         new_smc->sk.sk_err = new_smc->clcsock->sk->sk_err;
 248                 rc = sock_error(&new_smc->sk);
 249         }
 250
 251         return rc;
 252 }