[ipv4] Profile transmit and receive datapaths

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/net/ipv4.c

 #include <ipxe/settings.h>
 #include <ipxe/fragment.h>
 #include <ipxe/ipstat.h>
+#include <ipxe/profile.h>
 
 /** @file
  *
 	.stats = &ipv4_stats,
 };
 
+/** Transmit profiler */
+static struct profiler ipv4_tx_profiler __profiler = { .name = "ipv4.tx" };
+
+/** Receive profiler */
+static struct profiler ipv4_rx_profiler __profiler = { .name = "ipv4.rx" };
+
 /**
  * Add IPv4 minirouting table entry
  *
 	const void *ll_dest;
 	int rc;
 
+	/* Start profiling */
+	profile_start ( &ipv4_tx_profiler );
+
 	/* Update statistics */
 	ipv4_stats.out_requests++;
 
 		}
 	}
 
+	profile_stop ( &ipv4_tx_profiler );
 	return 0;
 
  err:
 	uint16_t pshdr_csum;
 	int rc;
 
+	/* Start profiling */
+	profile_start ( &ipv4_rx_profiler );
+
 	/* Update statistics */
 	ipv4_stats.in_receives++;
 	ipv4_stats.in_octets += iob_len ( iobuf );
 		return rc;
 	}
 
+	profile_stop ( &ipv4_rx_profiler );
 	return 0;
 
  err_header: