RDMA sniffing support for pcap

Implement capture support for offloaded RDMA traffic.  This uses the RDMA
verbs "flow steering" interface, which is available in the Linux kernel
since version 3.12.  The userspace interface is ibv_create_flow() - so
building this support in pcap adds a new dependency on libibverbs.

I added a new "rdmasniff" pcap module, which exposes RDMA devices under an
interface name equal to their libibverbs name.  The module uses the RDMA
verbs interface to create a receive queue with a flow steering rule that
gets a copy of all packets, even offloaded packets generated by or consumed
by the hardware.

The autoconf test for a usable version of libibverbs is a bit complicated
because ibv_create_flow() is defined as an inline function in the header
file, so we need to find the library and header and then try to link a
program to check if the API is usable (it appeared in libibverbs 1.1.8).

1 files changed, 412 insertions, 0 deletions

diff --git a/pcap-rdmasniff.c b/pcap-rdmasniff.c
new file mode 100644
index 00000000..d64ce05a
--- /dev/null
+++ b/pcap-rdmasniff.c
@@ -0,0 +1,412 @@
+/*
+ * Copyright (c) 2017 Pure Storage, Inc.
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote
+ * products derived from this software without specific prior written
+ * permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT
+ * OWNER 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "pcap-int.h"
+#include "pcap-rdmasniff.h"
+
+#include <infiniband/verbs.h>
+#include <stdlib.h>
+#include <sys/time.h>
+
+#if !defined(IBV_FLOW_ATTR_SNIFFER)
+#define IBV_FLOW_ATTR_SNIFFER	3
+#endif
+
+static const int RDMASNIFF_NUM_RECEIVES = 128;
+static const int RDMASNIFF_RECEIVE_SIZE = 10000;
+
+struct pcap_rdmasniff {
+	struct ibv_device *		rdma_device;
+	struct ibv_context *		context;
+	struct ibv_comp_channel *	channel;
+	struct ibv_pd *			pd;
+	struct ibv_cq *			cq;
+	struct ibv_qp *			qp;
+	struct ibv_flow *               flow;
+	struct ibv_mr *			mr;
+	u_char *			oneshot_buffer;
+	unsigned			port_num;
+	int                             cq_event;
+};
+
+static void
+rdmasniff_cleanup(pcap_t *handle)
+{
+	struct pcap_rdmasniff *priv = handle->priv;
+
+	ibv_dereg_mr(priv->mr);
+	ibv_destroy_flow(priv->flow);
+	ibv_destroy_qp(priv->qp);
+	ibv_destroy_cq(priv->cq);
+	ibv_dealloc_pd(priv->pd);
+	ibv_destroy_comp_channel(priv->channel);
+	ibv_close_device(priv->context);
+	free(priv->oneshot_buffer);
+
+	pcap_cleanup_live_common(handle);
+}
+
+static void
+rdmasniff_post_recv(pcap_t *handle, uint64_t wr_id)
+{
+	struct pcap_rdmasniff *priv = handle->priv;
+	struct ibv_sge sg_entry;
+	struct ibv_recv_wr wr, *bad_wr;
+
+	sg_entry.length = RDMASNIFF_RECEIVE_SIZE;
+	sg_entry.addr = (uintptr_t) handle->buffer + RDMASNIFF_RECEIVE_SIZE * wr_id;
+	sg_entry.lkey = priv->mr->lkey;
+
+	wr.wr_id = wr_id;
+	wr.num_sge = 1;
+	wr.sg_list = &sg_entry;
+	wr.next = NULL;
+
+	ibv_post_recv(priv->qp, &wr, &bad_wr);
+}
+
+static int
+rdmasniff_read(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
+{
+	struct pcap_rdmasniff *priv = handle->priv;
+	struct ibv_cq *ev_cq;
+	void *ev_ctx;
+	struct ibv_wc wc;
+	struct pcap_pkthdr pkth;
+	u_char *pktd;
+	int count = 0;
+
+	if (!priv->cq_event) {
+		if (ibv_get_cq_event(priv->channel, &ev_cq, &ev_ctx) < 0) {
+			return 0;
+		}
+		ibv_ack_cq_events(priv->cq, 1);
+		ibv_req_notify_cq(priv->cq, 0);
+		priv->cq_event = 1;
+	}
+
+	while (count < max_packets || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
+		if (ibv_poll_cq(priv->cq, 1, &wc) != 1) {
+			priv->cq_event = 0;
+			break;
+		}
+
+		if (wc.status != IBV_WC_SUCCESS) {
+			fprintf(stderr, "failed WC wr_id %lld status %d/%s\n",
+				(unsigned long long) wc.wr_id,
+				wc.status, ibv_wc_status_str(wc.status));
+			continue;
+		}
+
+		pkth.len = wc.byte_len;
+		pkth.caplen = min(pkth.len, handle->snapshot);
+		gettimeofday(&pkth.ts, NULL);
+
+		pktd = (u_char *) handle->buffer + wc.wr_id * RDMASNIFF_RECEIVE_SIZE;
+
+		if (handle->fcode.bf_insns == NULL ||
+		    bpf_filter(handle->fcode.bf_insns, pktd, pkth.len, pkth.caplen)) {
+			callback(user, &pkth, pktd);
+			++count;
+		}
+
+		rdmasniff_post_recv(handle, wc.wr_id);
+
+		if (handle->break_loop) {
+			handle->break_loop = 0;
+			return PCAP_ERROR_BREAK;
+		}
+	}
+
+	return count;
+}
+
+static void
+rdmasniff_oneshot(u_char *user, const struct pcap_pkthdr *h, const u_char *bytes)
+{
+	struct oneshot_userdata *sp = (struct oneshot_userdata *) user;
+	pcap_t *handle = sp->pd;
+	struct pcap_rdmasniff *priv = handle->priv;
+
+	*sp->hdr = *h;
+	memcpy(priv->oneshot_buffer, bytes, h->caplen);
+	*sp->pkt = priv->oneshot_buffer;
+}
+
+static int
+rdmasniff_activate(pcap_t *handle)
+{
+	struct pcap_rdmasniff *priv = handle->priv;
+	struct ibv_qp_init_attr qp_init_attr;
+	struct ibv_qp_attr qp_attr;
+	struct ibv_flow_attr flow_attr;
+	struct ibv_sge sg_entry;
+	struct ibv_recv_wr wr, *bad_wr;
+	struct ibv_port_attr port_attr;
+	int i;
+
+	priv->context = ibv_open_device(priv->rdma_device);
+	if (!priv->context) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to open device %s", handle->opt.device);
+		goto error;
+	}
+
+	priv->pd = ibv_alloc_pd(priv->context);
+	if (!priv->pd) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to alloc PD for device %s", handle->opt.device);
+		goto error;
+	}
+
+	priv->channel = ibv_create_comp_channel(priv->context);
+	if (!priv->channel) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to create comp channel for device %s", handle->opt.device);
+		goto error;
+	}
+
+	priv->cq = ibv_create_cq(priv->context, RDMASNIFF_NUM_RECEIVES,
+				 NULL, priv->channel, 0);
+	if (!priv->cq) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to create CQ for device %s", handle->opt.device);
+		goto error;
+	}
+
+	ibv_req_notify_cq(priv->cq, 0);
+
+	memset(&qp_init_attr, 0, sizeof qp_init_attr);
+	qp_init_attr.send_cq = qp_init_attr.recv_cq = priv->cq;
+	qp_init_attr.cap.max_recv_wr = RDMASNIFF_NUM_RECEIVES;
+	qp_init_attr.cap.max_recv_sge = 1;
+	qp_init_attr.qp_type = IBV_QPT_RAW_PACKET;
+	priv->qp = ibv_create_qp(priv->pd, &qp_init_attr);
+	if (!priv->qp) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to create QP for device %s", handle->opt.device);
+		goto error;
+	}
+
+	memset(&qp_attr, 0, sizeof qp_attr);
+	qp_attr.qp_state = IBV_QPS_INIT;
+	qp_attr.port_num = priv->port_num;
+	if (ibv_modify_qp(priv->qp, &qp_attr, IBV_QP_STATE | IBV_QP_PORT)) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to modify QP to INIT for device %s", handle->opt.device);
+		goto error;
+	}
+
+	memset(&qp_attr, 0, sizeof qp_attr);
+	qp_attr.qp_state = IBV_QPS_RTR;
+	if (ibv_modify_qp(priv->qp, &qp_attr, IBV_QP_STATE)) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to modify QP to RTR for device %s", handle->opt.device);
+		goto error;
+	}
+
+	memset(&flow_attr, 0, sizeof flow_attr);
+	flow_attr.type = IBV_FLOW_ATTR_SNIFFER;
+	flow_attr.size = sizeof flow_attr;
+	flow_attr.port = priv->port_num;
+	priv->flow = ibv_create_flow(priv->qp, &flow_attr);
+	if (!priv->flow) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to create flow for device %s", handle->opt.device);
+		goto error;
+	}
+
+	handle->bufsize = RDMASNIFF_NUM_RECEIVES * RDMASNIFF_RECEIVE_SIZE;
+	handle->buffer = malloc(handle->bufsize);
+	if (!handle->buffer) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to allocate receive buffer for device %s", handle->opt.device);
+		goto error;
+	}
+
+	priv->oneshot_buffer = malloc(RDMASNIFF_RECEIVE_SIZE);
+	if (!priv->oneshot_buffer) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to allocate oneshot buffer for device %s", handle->opt.device);
+		goto error;
+	}
+
+	priv->mr = ibv_reg_mr(priv->pd, handle->buffer, handle->bufsize, IBV_ACCESS_LOCAL_WRITE);
+	if (!priv->mr) {
+		pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
+			      "Failed to register MR for device %s", handle->opt.device);
+		goto error;
+	}
+
+
+	for (i = 0; i < RDMASNIFF_NUM_RECEIVES; ++i) {
+		rdmasniff_post_recv(handle, i);
+	}
+
+	if (!ibv_query_port(priv->context, priv->port_num, &port_attr) &&
+	    port_attr.link_layer == IBV_LINK_LAYER_INFINIBAND) {
+		handle->linktype = DLT_INFINIBAND;
+	} else {
+		handle->linktype = DLT_EN10MB;
+	}
+
+	if (handle->snapshot <= 0 || handle->snapshot > RDMASNIFF_RECEIVE_SIZE)
+		handle->snapshot = RDMASNIFF_RECEIVE_SIZE;
+
+	handle->offset = 0;
+	handle->read_op = rdmasniff_read;
+	handle->cleanup_op = rdmasniff_cleanup;
+	handle->setfilter_op = install_bpf_program;
+	handle->setdirection_op = NULL;
+	handle->set_datalink_op = NULL;
+	handle->getnonblock_op = pcap_getnonblock_fd;
+	handle->setnonblock_op = pcap_setnonblock_fd;
+	handle->oneshot_callback = rdmasniff_oneshot;
+	handle->selectable_fd = priv->channel->fd;
+
+	return 0;
+
+error:
+	if (priv->mr) {
+		ibv_dereg_mr(priv->mr);
+	}
+
+	if (priv->flow) {
+		ibv_destroy_flow(priv->flow);
+	}
+
+	if (priv->qp) {
+		ibv_destroy_qp(priv->qp);
+	}
+
+	if (priv->cq) {
+		ibv_destroy_cq(priv->cq);
+	}
+
+	if (priv->channel) {
+		ibv_destroy_comp_channel(priv->channel);
+	}
+
+	if (priv->pd) {
+		ibv_dealloc_pd(priv->pd);
+	}
+
+	if (priv->context) {
+		ibv_close_device(priv->context);
+	}
+
+	if (priv->oneshot_buffer) {
+		free(priv->oneshot_buffer);
+	}
+
+	return PCAP_ERROR;
+}
+
+pcap_t *
+rdmasniff_create(const char *device, char *ebuf, int *is_ours)
+{
+	struct pcap_rdmasniff *priv;
+	struct ibv_device **dev_list;
+	int numdev;
+	size_t namelen;
+	const char *port;
+	unsigned port_num;
+	int i;
+	pcap_t *p = NULL;
+
+	*is_ours = 0;
+
+	dev_list = ibv_get_device_list(&numdev);
+	if (!dev_list || !numdev) {
+		return NULL;
+	}
+
+	namelen = strlen(device);
+
+	port = strchr(device, ':');
+	if (port) {
+		port_num = strtoul(port + 1, NULL, 10);
+		if (port_num > 0) {
+			namelen = port - device;
+		} else {
+			port_num = 1;
+		}
+	} else {
+		port_num = 1;
+	}
+
+	for (i = 0; i < numdev; ++i) {
+		if (strlen(dev_list[i]->name) == namelen &&
+		    !strncmp(device, dev_list[i]->name, namelen)) {
+			*is_ours = 1;
+
+			p = pcap_create_common(ebuf, sizeof (struct pcap_rdmasniff));
+			if (p) {
+				p->activate_op = rdmasniff_activate;
+				priv = p->priv;
+				priv->rdma_device = dev_list[i];
+				priv->port_num = port_num;
+			}
+			break;
+		}
+	}
+
+	ibv_free_device_list(dev_list);
+	return p;
+}
+
+int
+rdmasniff_findalldevs(pcap_if_list_t *devlistp, char *err_str)
+{
+	struct ibv_device **dev_list;
+	int numdev;
+	int i;
+	int ret = 0;
+
+	dev_list = ibv_get_device_list(&numdev);
+	if (!dev_list || !numdev) {
+		return 0;
+	}
+
+	for (i = 0; i < numdev; ++i) {
+		if (!add_dev(devlistp, dev_list[i]->name, 0, "RDMA sniffer", err_str)) {
+			ret = -1;
+			goto out;
+		}
+	}
+
+out:
+	ibv_free_device_list(dev_list);
+	return ret;
+}