More error cleanups.

Handle the error codes from rte_eal_init().  Treat EACCES as a
permissions error when activating devices.  Treat ENOTSUP as meaning
"DPDK isn't available on this machine", which isn't a fatal error for
pcap_findalldevs() - we just don't find any DPDK devices.  Treate
EALREADY as meaning "we already called this", and note that we've done
so.  For other errors mentioned in the DPDK documentation, provide error
message strings as per the documentation for the error.

For pcap_findalldevs(), if we have no available Ethernet ports, just
report no devices, don't report a fatal error.

1 files changed, 170 insertions, 52 deletions

diff --git a/pcap-dpdk.c b/pcap-dpdk.c
index 2b67558d..f733c15f 100644
--- a/pcap-dpdk.c
+++ b/pcap-dpdk.c
@@ -115,6 +115,12 @@ env DPDK_CFG="--log-level=debug -l0 -dlibrte_pmd_e1000.so -dlibrte_pmd_ixgbe.so
 #include "pcap-dpdk.h"
 
 #define DPDK_DEF_LOG_LEV RTE_LOG_ERR
+//
+// This is set to 0 if we haven't initialized DPDK yet, 1 if we've
+// successfully initialized it, a negative value, which is the negative
+// of the rte_errno from rte_eal_init(), if we tried to initialize it
+// and got an error.
+//
 static int is_dpdk_pre_inited=0;
 #define DPDK_LIB_NAME "libpcap_dpdk"
 #define DPDK_DESC "Data Plane Development Kit (DPDK) Interface"
@@ -542,22 +548,43 @@ static int parse_dpdk_cfg(char* dpdk_cfg,char** dargv)
 }
 
 // only called once
-static int dpdk_pre_init(void)
+// Returns:
+//
+//    1 on success;
+//
+//    0 if "the EAL cannot initialize on this system", which we treat as
+//    meaning "DPDK isn't available";
+//
+//    a PCAP_ERROR_ code for other errors.
+static int dpdk_pre_init(char * ebuf)
 {
 	int dargv_cnt=0;
 	char *dargv[DPDK_ARGC_MAX];
 	char *ptr_dpdk_cfg = NULL;
-	int ret = PCAP_ERROR;
+	int ret;
 	// globale var
-	if (is_dpdk_pre_inited)
+	if (is_dpdk_pre_inited != 0)
 	{
-		// already inited
-		return 0;
+		// already inited; did that succeed?
+		if (is_dpdk_pre_inited < 0)
+		{
+			// failed
+			goto error;
+		}
+		else
+		{
+			// succeeded
+			return 1;
+		}
 	}
 	// check for root permission
+	// XXX - is it sufficient to call rte_eal_init() and check for
+	// EACCES?
 	if( geteuid() != 0)
 	{
 		RTE_LOG(ERR, USER1, "%s\n", DPDK_ERR_PERM_MSG);
+		pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+		    "DPDK requires that it run as root");
 		return PCAP_ERROR_PERM_DENIED;
 	}
 	// init EAL
@@ -575,12 +602,119 @@ static int dpdk_pre_init(void)
 	ret = rte_eal_init(dargv_cnt,dargv);
 	if (ret == -1)
 	{
-		// Error.
-		return PCAP_ERROR;
+		// Indicate that we've called rte_eal_init() by setting
+		// is_dpdk_pre_inited to the negative of the error code,
+		// and process the error.
+		is_dpdk_pre_inited = -rte_errno;
+		goto error;
 	}
 	// init succeeded, so we do not need to do it again later.
 	is_dpdk_pre_inited = 1;
-	return 0;
+	return 1;
+
+error:
+	switch (-is_dpdk_pre_inited)
+	{
+		case EACCES:
+			// This "indicates a permissions issue.".
+			RTE_LOG(ERR, USER1, "%s\n", DPDK_ERR_PERM_MSG);
+			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+			    "DPDK requires that it run as root");
+			return PCAP_ERROR_PERM_DENIED;
+
+		case EAGAIN:
+			// This "indicates either a bus or system
+			// resource was not available, setup may
+			// be attempted again."
+			// There's no such error in pcap, so I'm
+			// not sure what we should do here.
+			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+			    "Bus or system resource was not available");
+			break;
+
+		case EALREADY:
+			// This "indicates that the rte_eal_init
+			// function has already been called, and
+			// cannot be called again."
+			// That's not an error; set the "we've
+			// been here before" flag and return
+			// success.
+			is_dpdk_pre_inited = 1;
+			return 1;
+
+		case EFAULT:
+			// This "indicates the tailq configuration
+			// name was not found in memory configuration."
+			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+			    "The tailq configuration name was not found in the memory configuration");
+			return PCAP_ERROR;
+
+		case EINVAL:
+			// This "indicates invalid parameters were
+			// passed as argv/argc."  Those came from
+			// the configuration file.
+			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+			    "The configuration file has invalid parameters");
+			break;
+
+		case ENOMEM:
+			// This "indicates failure likely caused by
+			// an out-of-memory condition."
+			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+			    "Out of memory");
+			break;
+
+		case ENODEV:
+			// This "indicates memory setup issues."
+			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+			    "An error occurred setting up memory");
+			break;
+
+		case ENOTSUP:
+			// This "indicates that the EAL cannot
+			// initialize on this system."  We treat
+			// that as meaning DPDK isn't available
+			// on this machine, rather than as a
+			// fatal error, and let our caller decide
+			// whether that's a fatal error (if trying
+			// to activate a DPDK device) or not (if
+			// trying to enumerate devices).
+			return 0;
+
+		case EPROTO:
+			// This "indicates that the PCI bus is
+			// either not present, or is not readable
+			// by the eal."  Does "the PCI bus is not
+			// present" mean "this machine has no PCI
+			// bus", which strikes me as a "not available"
+			// case?  If so, should "is not readable by
+			// the EAL" also something we should treat
+			// as a "not available" case?  If not, we
+			// can't distinguish between the two, so
+			// we're stuck.
+			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+			    "PCI bus is not present or not readable by the EAL");
+			break;
+
+		case ENOEXEC:
+			// This "indicates that a service core
+			// failed to launch successfully."
+			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
+			    "A service core failed to launch successfully");
+			break;
+
+		default:
+			//
+			// That's not in the list of errors in
+			// the documentation; let it be reported
+			// as an error.
+			//
+			dpdk_fmt_errmsg_for_rte_errno(ebuf,
+			    PCAP_ERRBUF_SIZE, -is_dpdk_pre_inited);
+			break;
+	}
+	// Error.
+	return PCAP_ERROR;
 }
 
 static int pcap_dpdk_activate(pcap_t *p)
@@ -599,33 +733,26 @@ static int pcap_dpdk_activate(pcap_t *p)
 	struct rte_eth_link link;
 	do{
 		//init EAL
-		ret = dpdk_pre_init();
+		char dpdk_pre_init_errbuf[PCAP_ERRBUF_SIZE];
+		ret = dpdk_pre_init(dpdk_pre_init_errbuf);
 		if (ret < 0)
 		{
 			// This returns a negative value on an error.
-			// That's either PCAP_ERROR_PERM_DENIED if
-			// you're not running as root, or PCAP_ERROR
-			// if rte_eal_init() fails.
-			//
-			// If it returned PCAP_ERROR, provide an error
-			// message based on rte_errno.  Otherwise, the
-			// error message has already been filled in.
-			if (ret == PCAP_ERROR)
-			{
-				dpdk_fmt_errmsg_for_rte_errno(p->errbuf,
-				    PCAP_ERRBUF_SIZE, rte_errno,
-				    "dpdk error: Init failed with device %s",
-				    p->opt.device);
-			}
-			else
-			{
-				pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
-				    "Can't open device %s: DPDK requires that it run as root",
-				    p->opt.device);
-			}
+			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			    "Can't open device %s: %s",
+			    p->opt.device, dpdk_pre_init_errbuf);
 			// ret is set to the correct error
 			break;
 		}
+		if (ret == 0)
+		{
+			// This means DPDK isn't available on this machine.
+			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			    "Can't open device %s: DPDK is not available on this machine",
+			    p->opt.device);
+			return PCAP_ERROR_NO_SUCH_DEVICE;
+		}
+			
 		ret = dpdk_init_timer(pd);
 		if (ret<0)
 		{
@@ -845,37 +972,28 @@ int pcap_dpdk_findalldevs(pcap_if_list_t *devlistp, char *ebuf)
 	char mac_addr[DPDK_MAC_ADDR_SIZE];
 	char pci_addr[DPDK_PCI_ADDR_SIZE];
 	do{
-		ret = dpdk_pre_init();
+		char dpdk_pre_init_errbuf[PCAP_ERRBUF_SIZE];
+		ret = dpdk_pre_init(dpdk_pre_init_errbuf);
 		if (ret < 0)
 		{
 			// This returns a negative value on an error.
-			// That's either PCAP_ERROR_PERM_DENIED if
-			// you're not running as root, or PCAP_ERROR
-			// if rte_eal_init() fails.
-			//
-			// If it returned PCAP_ERROR, provide an error
-			// message based on rte_errno.  Otherwise, the
-			// error message has already been filled in.
-			if (ret == PCAP_ERROR)
-			{
-				dpdk_fmt_errmsg_for_rte_errno(ebuf,
-				    PCAP_ERRBUF_SIZE, rte_errno,
-				    "dpdk error: Init failed");
-			}
-			else
-			{
-				pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
-				    "DPDK requires that it run as root");
-			}
-			// ret is set to the correct error
+			pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			    "Can't open device %s: %s",
+			    p->opt.device, dpdk_pre_init_errbuf);
+			ret = PCAP_ERRNO;
+			break;
+		}
+		if (ret == 0)
+		{
+			// This means DPDK isn't available on this machine.
+			// That just means "don't return any devices".
 			break;
 		}
 		nb_ports = rte_eth_dev_count_avail();
 		if (nb_ports == 0)
 		{
-			pcap_snprintf(ebuf, PCAP_ERRBUF_SIZE,
-			    "DPDK error: No Ethernet ports");
-			ret = PCAP_ERROR;
+			// That just means "don't return any devices".
+			ret = 0;
 			break;
 		}
 		for (unsigned int i=0; i<nb_ports; i++){