From 6112194e8e67554317e75d52c259c6d6a3606438 Mon Sep 17 00:00:00 2001
From: Babak Farrokhi <babak@farrokhi.net>
Date: Wed, 14 Nov 2018 12:55:28 +0330
Subject: [PATCH] Add ifcounters program that displays interface counters

---
 ifcounters/Makefile     |  24 ++++++++
 ifcounters/ifcounters.c | 123 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 147 insertions(+)
 create mode 100644 ifcounters/Makefile
 create mode 100644 ifcounters/ifcounters.c

diff --git a/ifcounters/Makefile b/ifcounters/Makefile
new file mode 100644
index 0000000..26bbbe2
--- /dev/null
+++ b/ifcounters/Makefile
@@ -0,0 +1,24 @@
+CC?=
+PREFIX?=/usr/local
+CPPFLAGS=-I$(PREFIX)/include
+CFLAGS=-Wall -Wextra -g -O2 -pipe -funroll-loops -ffast-math -fno-strict-aliasing
+CFLAGS+=$(CPPFLAGS)
+LDFLAGS=-L$(PREFIX)/lib
+LDLIBS=-lm
+RM?=rm -f
+
+IFCOUNTERS = ifcounters
+OBJ = ifcounters.o
+
+all: $(IFCOUNTERS)
+
+$(IFCOUNTERS): $(OBJ)
+	$(CC) $(LDFLAGS) $(OBJ) $(LDLIBS) -o $(IFCOUNTERS)
+
+install: all
+	install -s -C $(IFCOUNTERS) $(PREFIX)/bin
+
+clean:
+	$(RM) *.o *.a a.out core *.core temp.* $(IFCOUNTERS)
+	$(RM) -r *.dSYM
+
diff --git a/ifcounters/ifcounters.c b/ifcounters/ifcounters.c
new file mode 100644
index 0000000..adc5bb7
--- /dev/null
+++ b/ifcounters/ifcounters.c
@@ -0,0 +1,123 @@
+#include <stdio.h>
+#include <ifaddrs.h>
+#include <net/if.h>
+#include <string.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define IFA_STAT(s)     (((struct if_data *)ifa->ifa_data)->ifi_ ## s)
+
+#define PACKAGE_NAME    "ifcounters"
+#define PACKAGE_VERSION "0.1"
+
+void show_help()
+{
+    printf(
+            "Usage: ifcounters [-v] [-h] [-b|-p|-e|-m|-q] interface\n" \
+            "\n" \
+            "Options:\n" \
+            "   -b      Input/Output Bytes counter\n" \
+            "   -p      Input/Output Unicast Packets counter\n" \
+            "   -e      Input/Output Errors counter\n" \
+            "   -m      Input/Output Multicast Packets counter\n" \
+            "   -q      Input/Output Queue Drops counter\n" \
+            "   -v      Display version information\n" \
+            "   -h      Display this help message\n"
+            );
+
+}
+
+void show_version()
+{
+    printf("%s %s\n", PACKAGE_NAME, PACKAGE_VERSION);
+    printf("Copyright (c) 2018 by Babak Farrokhi <babak@farrokhi.net>\n");
+}
+
+int main(int argc, char **argv)
+{
+    struct ifaddrs *ifap, *ifa;
+    char *ifname, *param;
+    int flag, c;
+
+    flag = 0;
+
+    if (argc < 2) {
+        show_help();
+        exit(0);
+    }
+
+    while ((c = getopt(argc, argv, "hvb:p:e:m:q:")) != -1) {
+
+        switch (c) {
+            case 'h':
+                show_help();
+                exit(0);
+            case 'v':
+                show_version();
+                exit(0);
+            case 'b':
+            case 'p':
+            case 'e':
+            case 'm':
+            case 'q':
+                flag = c;
+                param = strdup(optarg);
+                break;
+            case '?':
+            default:
+                show_help();
+                printf("\n");
+                show_version();
+                exit(1);
+        }
+    }
+
+    argc -= optind;
+    argv += optind;
+
+    if (flag == 0) {
+        show_help();
+        exit(1);
+    }
+
+    if (getifaddrs(&ifap) != 0) {
+        fprintf(stderr, "error\n");
+    }
+    else {
+        for (ifa = ifap; ifa; ifa= ifa->ifa_next) {
+            ifname = ifa->ifa_name;
+
+            if (strcmp(ifa->ifa_name, param) == 0) {
+                switch (flag) {
+                    case 'b':
+                        printf("rbytes.value %lu\nobytes.value %lu\n", IFA_STAT(ibytes), IFA_STAT(obytes));
+                        break;
+                    case 'p':
+                        printf("rpackets.value %lu\nopackets.value %lu\n", IFA_STAT(ipackets), IFA_STAT(opackets));
+                        break;
+                    case 'e':
+                        printf("rerrors.value %lu\noerrors.value %lu\n", IFA_STAT(ierrors), IFA_STAT(oerrors));
+                        break;
+                    case 'm':
+                        printf("rmcasts.value %lu\nomcasts.value %lu\n", IFA_STAT(imcasts), IFA_STAT(omcasts));
+                        break;
+                    case 'q':
+                        printf("rqdrops.value %lu\noqdrops.value %lu\n", IFA_STAT(iqdrops), IFA_STAT(oqdrops));
+                        break;
+                    default:
+                        printf("invalid flag");
+                        exit(1);
+                }
+                exit(0);
+            }
+
+            while (ifa->ifa_next != NULL && 
+                    (strcmp(ifa->ifa_next->ifa_name, ifname) == 0))  {
+                ifa = ifa->ifa_next;
+            }
+        }
+        printf("Unknown interface: %s\n", param);
+        exit(1);
+    }
+}