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https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
a63ba13eec
The crafted header start address is from a driver supplied buffer, which one can reasonably expect to be aligned on a 4-bytes boundary. However ATM the TSO helper API is only used by ethernet drivers and the tcp header will then be aligned to a 2-bytes only boundary from the header start address. Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com> Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com> Signed-off-by: David S. Miller <davem@davemloft.net>
78 lines
2.1 KiB
C
78 lines
2.1 KiB
C
#include <linux/export.h>
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#include <net/ip.h>
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#include <net/tso.h>
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#include <asm/unaligned.h>
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/* Calculate expected number of TX descriptors */
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int tso_count_descs(struct sk_buff *skb)
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{
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/* The Marvell Way */
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return skb_shinfo(skb)->gso_segs * 2 + skb_shinfo(skb)->nr_frags;
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}
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EXPORT_SYMBOL(tso_count_descs);
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void tso_build_hdr(struct sk_buff *skb, char *hdr, struct tso_t *tso,
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int size, bool is_last)
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{
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struct iphdr *iph;
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struct tcphdr *tcph;
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int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
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int mac_hdr_len = skb_network_offset(skb);
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memcpy(hdr, skb->data, hdr_len);
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iph = (struct iphdr *)(hdr + mac_hdr_len);
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iph->id = htons(tso->ip_id);
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iph->tot_len = htons(size + hdr_len - mac_hdr_len);
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tcph = (struct tcphdr *)(hdr + skb_transport_offset(skb));
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put_unaligned_be32(tso->tcp_seq, &tcph->seq);
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tso->ip_id++;
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if (!is_last) {
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/* Clear all special flags for not last packet */
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tcph->psh = 0;
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tcph->fin = 0;
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tcph->rst = 0;
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}
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}
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EXPORT_SYMBOL(tso_build_hdr);
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void tso_build_data(struct sk_buff *skb, struct tso_t *tso, int size)
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{
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tso->tcp_seq += size;
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tso->size -= size;
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tso->data += size;
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if ((tso->size == 0) &&
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(tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
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skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
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/* Move to next segment */
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tso->size = frag->size;
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tso->data = page_address(frag->page.p) + frag->page_offset;
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tso->next_frag_idx++;
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}
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}
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EXPORT_SYMBOL(tso_build_data);
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void tso_start(struct sk_buff *skb, struct tso_t *tso)
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{
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int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
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tso->ip_id = ntohs(ip_hdr(skb)->id);
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tso->tcp_seq = ntohl(tcp_hdr(skb)->seq);
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tso->next_frag_idx = 0;
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/* Build first data */
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tso->size = skb_headlen(skb) - hdr_len;
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tso->data = skb->data + hdr_len;
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if ((tso->size == 0) &&
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(tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
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skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
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/* Move to next segment */
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tso->size = frag->size;
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tso->data = page_address(frag->page.p) + frag->page_offset;
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tso->next_frag_idx++;
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}
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}
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EXPORT_SYMBOL(tso_start);
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