[PATCH v2 1/3] pktgen: Parse internet mix (imix) input

From: Nicholas Richardson
Date: Tue Aug 10 2021 - 15:02:19 EST


From: Nick Richardson <richardsonnick@xxxxxxxxxx>

Adds "imix_weights" command for specifying internet mix distribution.

The command is in this format:
"imix_weights size_1,weight_1 size_2,weight_2 ... size_n,weight_n"
where the probability that packet size_i is picked is:
weight_i / (weight_1 + weight_2 + .. + weight_n)

The user may provide up to 100 imix entries (size_i,weight_i) in this
command.

The user specified imix entries will be displayed in the "Params"
section of the interface output.

Values for clone_skb > 0 is not supported in IMIX mode.

Summary of changes:
Add flag for enabling internet mix mode.
Add command (imix_weights) for internet mix input.
Return -ENOTSUPP when clone_skb > 0 in IMIX mode.
Display imix_weights in Params.
Create data structures to store imix entries and distribution.

Signed-off-by: Nick Richardson <richardsonnick@xxxxxxxxxx>
---
net/core/pktgen.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 96 insertions(+)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 7e258d255e90..a7e45eaccef7 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -175,6 +175,8 @@
#define IP_NAME_SZ 32
#define MAX_MPLS_LABELS 16 /* This is the max label stack depth */
#define MPLS_STACK_BOTTOM htonl(0x00000100)
+/* Max number of internet mix entries that can be specified in imix_weights. */
+#define MAX_IMIX_ENTRIES 20

#define func_enter() pr_debug("entering %s\n", __func__);

@@ -242,6 +244,12 @@ static char *pkt_flag_names[] = {
#define VLAN_TAG_SIZE(x) ((x)->vlan_id == 0xffff ? 0 : 4)
#define SVLAN_TAG_SIZE(x) ((x)->svlan_id == 0xffff ? 0 : 4)

+struct imix_pkt {
+ u64 size;
+ u64 weight;
+ u64 count_so_far;
+};
+
struct flow_state {
__be32 cur_daddr;
int count;
@@ -343,6 +351,10 @@ struct pktgen_dev {
__u8 traffic_class; /* ditto for the (former) Traffic Class in IPv6
(see RFC 3260, sec. 4) */

+ /* IMIX */
+ unsigned int n_imix_entries;
+ struct imix_pkt imix_entries[MAX_IMIX_ENTRIES];
+
/* MPLS */
unsigned int nr_labels; /* Depth of stack, 0 = no MPLS */
__be32 labels[MAX_MPLS_LABELS];
@@ -552,6 +564,16 @@ static int pktgen_if_show(struct seq_file *seq, void *v)
(unsigned long long)pkt_dev->count, pkt_dev->min_pkt_size,
pkt_dev->max_pkt_size);

+ if (pkt_dev->n_imix_entries > 0) {
+ seq_puts(seq, " imix_weights: ");
+ for (i = 0; i < pkt_dev->n_imix_entries; i++) {
+ seq_printf(seq, "%llu,%llu ",
+ pkt_dev->imix_entries[i].size,
+ pkt_dev->imix_entries[i].weight);
+ }
+ seq_puts(seq, "\n");
+ }
+
seq_printf(seq,
" frags: %d delay: %llu clone_skb: %d ifname: %s\n",
pkt_dev->nfrags, (unsigned long long) pkt_dev->delay,
@@ -792,6 +814,62 @@ static int strn_len(const char __user * user_buffer, unsigned int maxlen)
return i;
}

+/* Parses imix entries from user buffer.
+ * The user buffer should consist of imix entries separated by spaces
+ * where each entry consists of size and weight delimited by commas.
+ * "size1,weight_1 size2,weight_2 ... size_n,weight_n" for example.
+ */
+static ssize_t get_imix_entries(const char __user *buffer,
+ struct pktgen_dev *pkt_dev)
+{
+ const int max_digits = 10;
+ int i = 0;
+ long len;
+ char c;
+
+ pkt_dev->n_imix_entries = 0;
+
+ do {
+ unsigned long weight;
+ unsigned long size;
+
+ len = num_arg(&buffer[i], max_digits, &size);
+ if (len < 0)
+ return len;
+ i += len;
+ if (get_user(c, &buffer[i]))
+ return -EFAULT;
+ /* Check for comma between size_i and weight_i */
+ if (c != ',')
+ return -EINVAL;
+ i++;
+
+ if (size < 14 + 20 + 8)
+ size = 14 + 20 + 8;
+
+ len = num_arg(&buffer[i], max_digits, &weight);
+ if (len < 0)
+ return len;
+ if (weight <= 0)
+ return -EINVAL;
+
+ pkt_dev->imix_entries[pkt_dev->n_imix_entries].size = size;
+ pkt_dev->imix_entries[pkt_dev->n_imix_entries].weight = weight;
+
+ i += len;
+ if (get_user(c, &buffer[i]))
+ return -EFAULT;
+
+ i++;
+ pkt_dev->n_imix_entries++;
+
+ if (pkt_dev->n_imix_entries > MAX_IMIX_ENTRIES)
+ return -E2BIG;
+ } while (c == ' ');
+
+ return i;
+}
+
static ssize_t get_labels(const char __user *buffer, struct pktgen_dev *pkt_dev)
{
unsigned int n = 0;
@@ -960,6 +1038,18 @@ static ssize_t pktgen_if_write(struct file *file,
return count;
}

+ if (!strcmp(name, "imix_weights")) {
+ if (pkt_dev->clone_skb > 0)
+ return -EINVAL;
+
+ len = get_imix_entries(&user_buffer[i], pkt_dev);
+ if (len < 0)
+ return len;
+
+ i += len;
+ return count;
+ }
+
if (!strcmp(name, "debug")) {
len = num_arg(&user_buffer[i], 10, &value);
if (len < 0)
@@ -1082,10 +1172,16 @@ static ssize_t pktgen_if_write(struct file *file,
len = num_arg(&user_buffer[i], 10, &value);
if (len < 0)
return len;
+ /* clone_skb is not supported for netif_receive xmit_mode and
+ * IMIX mode.
+ */
if ((value > 0) &&
((pkt_dev->xmit_mode == M_NETIF_RECEIVE) ||
!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))
return -ENOTSUPP;
+ if (value > 0 && pkt_dev->n_imix_entries > 0)
+ return -EINVAL;
+
i += len;
pkt_dev->clone_skb = value;

--
2.32.0.605.g8dce9f2422-goog